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Re: Kit Amp

Bill Turner
 

ORIGINAL MESSAGE:

On Wed, 25 Oct 2006 14:57:52 -0000, "ad4hk2004" <ad4hk2004@...>
wrote:

The price of metal
stampings and machined parts that have been drilled and tapped,
cleaned, powder coated and baked, then shipped to your plant, will
take your breath away...
------------ REPLY FOLLOWS ------------

Perhaps it could be done with blank metal pieces and a paper template
for the builder to drill and finish himself?

Your other comments about "key down for four hours" etc, are well
taken. Everything considered, it's not likely to happen. If it were
cost-effective, Heathkit would still be in business.

The other part of the equation is that hams who are real technicians
are becoming a rare species. I hate the phrase "appliance operator"
but it often applies, I'm sorry to say. Not to this group, though. :-)

Bill, W6WRT
Re: Grounding Grids on 3-500Z's

 

On Oct 27, 2006, at 12:22 AM, pentalab wrote:

--- In ham_amplifiers@..., R L Measures <r@...> wrote:


On Oct 26, 2006, at 2:11 PM, Phil Clements wrote:

I received a lot of interesting posts when I asked about
repairing
a grid
bypass choke fire on a customer's SB-220.
Another fix was to replace the 200 pf bypass caps with at least
500 pf
units, and replace the RF chokes with fusing resistors.
RICH SEZ... In my experiences, a suitable glitch-R in the HV+ helps
prevent grid- filament shorts.

### agreed... when stuff "goes nuts"... the glitch will LIMIT
current..... precede the glitch with a HV fuse... and that combo is
excellent.
? What failure does the HV fuse protect against with thoriated
tungsten filament tubes?

Come glitch time.. it's always limiting , followed
by HV fuse opening....saves all sorts of destruction... whether
cuzed by parasitics.. or anything else.
...
The question of the day is why Henry chose a more expensive
approach than
any of their competitors?
### I wondered about that scheme too........ most bizzare
contraption ever devised.... and those amps work just great with the
grids directly grnded to the chassis.. and a grid fuse installed..
plus glich/hv fuse etc. I'm sure Rube Goldberg and Muncy both
worked for Henry Radio at one time.



RICH SEZ.. A friend went the Henry booth at a Hamvention and
asked one of the Henry engineers why none of the Henry 3-500Z
amplifiers currently had 160m coverage. The reply: 1.8MHz is
below the 3-500Z's low- frequency cutoff.

### LOL. Joke right ??
? No


Early Henry amplifiers had a problem welding the contacts of
the power contactor that was used to switch them on and off.
Instead of doing the obvious -- adding a step-start relay and 2
step-start resistors, Henry's solution was to install an uncheap
humungous power contactor with mercury-wetted contacts.

### You never install 2 x step start resistors..... it's total loop
resistance we are concerned with here. Just install one step
start resistor.. in one leg of the 240 line.
? One step-start R will not work with amplifiers that are made for
dual 120v/240v operation.

I use a 25 ohm
unit... consisting of a pair of 50 ohm resistor's in parallel [50
w /100w each]. The paralleled approach offers redundancy...if one
ever opened... still got the 2nd one.. albeit 50 ohms. All thta's
neede is a SPST-DM contactor or SPST relay to sort out the one
step start resistor. Stick one per leg,, and you then need a
DPST relay/contactor to short it out.
? Correct, and it will step-start on either 120v or 240v.

### Mercury wetted contacts is another waste of time.
? ... and money.

Loads of
good contactor's out there. A standard contactor is just 2 sets
of contacts.. in series... PER POLE, so u end up with no arcing
when trying to open a load off. [u split the arc into two
simultaneous arcs = zero arc].
? I disagree. Inductive loads can produce 25x the operating
potential when current stops.

They are called DPDT-DM [double
make]. Regular contactor's have the distinct advantage that
their contacts are all easily field replaceable. I clean new ones
up... slop some "cool amp" silver plating compound on em... and
zero ohms guaranteed everytime.
? Zero-ohms without liquid helium cooling?

You can slop a tiny layer
of "conducto lube" [pure silver powder, suspended in grease, made
for moving/sliding contacts] on em as well..... results in 110 %
success every time.... last a long time. Too many stock
contacts don't quite result in zero ohms when pushing on em with
ur fingers.. really hard.

### My conclusion is Henty doesn't "get it" with some aspects of
their stuff. I have their 10 kw LP filter.... compact,
superbly designed... then they can't build a HV supply right.
Their resonant choke scheme looks good on paper.. then Henry ends
up using one bad HV xfmr maker after another after another. IMO...
dump the resonant choke scheme alltogether, install a hypersil C
core, and a heavy duty FWB [1 kv- 6A -400 A surge diodes are dirt
cheap] , and a large C input filter.... and step start. If ur
gonna stick a ton of extra weight in there... add it to the plate
xfmr... not a choke.





I would love to hear the reasoning and experiences
when they built up the prototype of this amp.
### They probably all dragged out their 1934 engineering books.




The direct-grounding camp all reports no problems since their
mod. and swearby that solution.

### Yeah, I swear by it.... esp after 40 e-mails from other SB-
220/221/TL-922 owners, who also swear by it. It's worth it
anyway... guranteed 22-25 watts LESS drive required. I have yet
to hear from any of those guys about parasitic problems either.
The guys with the TL-922's all said.. after directly grnding the
grids to the chassis.... they could all remove the after market
nichrome suppressor's... and re-install the stock kenwood
suppressor's..... rock stable.



RICH SEZ....The AL-82 and uses directly-grounded 3-500Z grid pins
and it has a well-deserved reputation for arcing open contacts on
its bandswitch.

### That's an apples and concrete comparison Rich. The AL-82 [2
x 3-500Z} is called the "firecracker" by the east coast crowd. The
AL-82 is an abortion..... along with it's little bastard child.. the
AL-80B. Both of em like to spit out flames... new right out of the
box..... and that's with just one good short coax.. from amp to
dummy load.... and using PTT... and keeping the loading heavy. The
layout is screwed up in both those amps. Notice the extra
bandswitch wafer's, and extra caps switched in across the bandswitch
itself..... it appears they have an internal resonance bandswitch
problem...esp on 17m.
The toasted bandswitch in the jpg has damage mostly where the 10m and 15m contacts used to be.

### These guys just don't get it. You gotta use correct size
components to start with...
The bandswitch has a 5000v BD and the max potential during operation
is c. 3000v.


and NO wire from any bandswitch
contacts..... just wide, silver plated strap
Round conductors exhibit uniform RF current distribution, flat
conductors don't.

...
The other three solutions speak for themselves, as there
must be thousands of 3-500Z's operating in the field with long
track records. The problems seem to increase when replacing Eimac
tubes with knock-offs.

RICH SEZ... Most of the grid-filament shorted tubes that I have high-
potted were Eimacs.

### All eimac 3=500Z's have a MU= 130 Knock off's are all
MU=200.
Then why do RF Parts 3-500s have the same ZSAC as Eimacs in a SB-220
or TL-922 while Amperex 3-500s exhibit a lower ZSAC?


...end
R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org
Re: w5uc's pi net spread sheet...deluxe.

 

¿ªÔÆÌåÓý

Nice pix of the 6 mtr project.? Looks like you have done layout work before. Living in Lufkin, TX, do you work for the measuring device outfit?? Have an old Lufkin 50 ft. tape measure that must be 60-70 years or so old, (leather covered, snap open handle on the side) still works like a dream.
Liked the shot of the steam engine in the woods, too.
73,
Gary...wa6fgi
?

----- Original Message -----
From: pentalab
Sent: Thursday, October 26, 2006 11:24 PM
Subject: [ham_amplifiers] Re: w5uc's pi net spread sheet...deluxe.

--- In ham_amplifiers@yahoogroups.com, "Mike\(W5UC\) &
Kathy\(K5MWH\)" wrote:
>
> Good Morning Noel & All:
>
>
>
> I have started construction on a pair of GI-7b's for 6 meters, but
6 mtrs
> cooled and 160 Mtrs got ready to come on for the winter. You can
see my
> progress, or lack thereof on my web page.
>
> >
> 73,
>
> Mike, W5UC
>
>

#### then click on..."stuff" I tried the pi net for my tuned
inputs.... and it's slick.... since it does ALL bands at once. By
tweaking the Q in tiny increments... it spat out virtually
identical results to what we are using on both the 3000 A7 amp..
and the 6000A7 amp. Now here's the kicker..... the tube's input
Z may be a little lower than 50 ohms in my case.... and when
feeding with 50 ohm coax.... u will end up with a conjugate
match... so allow leeway [esp on 160m].. esp on the C2 cap closest
to cathode.

### another caveat with tuned inputs is... I ran 50 ohm coax
from the output of my vraiable tuned inputs... through a bird.. then
into dummy load..... could be tweaked dead flat on all bands. Trbl
was.... with exactly 200 w going in [had another bird on input
side], power out of tuned input , on low bands was around 195 w.
On 17-15... dropped to 160w ! Had to increase the L very
slightly.. reduce the C1 C2 caps a tiny bit.... then power out of
tuned inputs shot up to 193 watts.... and all is well. Point
is... don't run the Q too high.. run it high enough [on high bands
only] so power out of the tuned input on test jig just drops off...
then reduce the Q slightly [more L, less C1 + C2]

## Once output bird is removed.. and coax routed to tube's
cathode, etc.... and in operation on the air/dummy load... C1 + C2
caps are very close to the test set up..... just a little tweaking
on em resulted in ZERO watts reflected power... MAX grid current on
tube....and xcvr/ipa happy.

## Have not tried the pi spread sheets for big pi output... yet.
Dunno whether they factor in the stray L between anode and PI or
not.. as this has a huge effect... since any stray L b4 the PI
will drop/transform the plate load Z.. like a rock... which is
fine... but the PI has to be designed around a lower plate load Z.

all in all... superb sheet. Gotta spend more time with it. It
would be nice to have something that calculates the expected
peak/rms currents and rf voltages across all the components....
including the plate block cap, anode to chassis path, C1 C2...
and coil... + ant current. Then it makes it easier to size
stuff.

later.... Jim VE7RF
>
>

Re: w5uc's pi net spread sheet...deluxe.

Tony King - W4ZT
 

pentalab wrote:

-- In ham_amplifiers@..., "Mike&#92;(W5UC&#92;) &
Kathy&#92;(K5MWH&#92;)" <w5uc@...> wrote:
<snip>
#### then click on..."stuff" I tried the pi net for my tuned inputs.... and it's slick.... since it does ALL bands at once. By tweaking the Q in tiny increments... it spat out virtually identical results to what we are using on both the 3000 A7 amp.. and the 6000A7 amp. Now here's the kicker..... the tube's input Z may be a little lower than 50 ohms in my case.... and when feeding with 50 ohm coax.... u will end up with a conjugate match... so allow leeway [esp on 160m].. esp on the C2 cap closest to cathode.
When I put the sheet together, I was concerned that it wouldn't do tuned inputs well so I am glad to hear that it actually worked there.
<snip>
## Have not tried the pi spread sheets for big pi output... yet. Dunno whether they factor in the stray L between anode and PI or not.. as this has a huge effect... since any stray L b4 the PI will drop/transform the plate load Z.. like a rock... which is fine... but the PI has to be designed around a lower plate load Z.
No real factor for strays since they are different for every situation and tube. It wouldn't be that difficult to add a field so you could plug in your own strays and then let it use those for the final output.

all in all... superb sheet. Gotta spend more time with it. It would be nice to have something that calculates the expected peak/rms currents and rf voltages across all the components.... including the plate block cap, anode to chassis path, C1 C2... and coil... + ant current. Then it makes it easier to size stuff. later.... Jim VE7RF
Now that's an idea... I'd be happy to take a stab at including such things. We'll have to talk off line and see what you'd want.

I didn't make that thing as a cure all, but I really did want a tool to do "what if" with and displaying all the bands data at one time was a big part of that.

Thanks for your comments.

73, Tony W4ZT
Re: chimney material

Tony King - W4ZT
 

pentalab wrote:
<snip>
### I'm into high level experimentation... up to a point. Between soft x rays, heat, globs of RF, 8000Vdc, etc.... Teflon seemed like a sure fire method/zero brainer. [u know it's gonna work ]
There's nothing better!
<snip>
### agreed.... but I didn't want to make a major project out of a chimney. The trbl with teflon sheeting, etc... is u gotta anchor it to the chassis. At least with my original Straight up and down stove pipe chimney..it was 1/4" thick teflon, and so heavy, it's weight alone held it to the chassis. As noted b4... it restricted the intake air too much.
Jim, have you considered sub mounting the tube? Current methods dictate cutting lots of holes around the tube to allow the air to flow. If you sub mount the tube by an inch, mount it on a solid aluminum or, better still, copper plate, you can get LOTS of air up around the seals and up to the anode without a huge wide pattern of holes around the tube. Then a straight chimney will work and you're back to a nice Teflon chimney that's easy to make though a little expensive.
<snip>
73, Tony W4ZT
Re: Grounding Grids on 3-500Z's

pentalab
 

--- In ham_amplifiers@..., R L Measures <r@...> wrote:


On Oct 26, 2006, at 2:11 PM, Phil Clements wrote:

I received a lot of interesting posts when I asked about
repairing
a grid
bypass choke fire on a customer's SB-220.
Another fix was to replace the 200 pf bypass caps with at least
500 pf
units, and replace the RF chokes with fusing resistors.
RICH SEZ... In my experiences, a suitable glitch-R in the HV+ helps
prevent grid- filament shorts.

### agreed... when stuff "goes nuts"... the glitch will LIMIT
current..... precede the glitch with a HV fuse... and that combo is
excellent. Come glitch time.. it's always limiting , followed
by HV fuse opening....saves all sorts of destruction... whehter
cuzed by parasitics.. or anything else.

Absolutely nobody suggested returning the circuit to original
factory specs.
## The original factory spec just copied the L4B that came out in 1969
and the earlier L4 [1964] verbatim... they were all wrong... still
are.



On the far-end of the spectrum from direct-grounding of the
grids
has to be
the Henry 2K-4. No RF chokes are utilized, but there are 18-
.003
mfd bypass
caps, 12- 10 ohm resistors, and a 250 ohm grid ma adjust
potentiometer, all
hanging from grid pins to chassis! Grid pins (pin #4) of each
tube are
strapped together. Pins 2 and 3 on each tube are strapped
together,
but not
strapped tube-to-tube. Also, Henry chose to use 2- 150 ohm
resistors in
parallel with the coil on the parasitic suppressors.

The question of the day is why Henry chose a more expensive
approach than
any of their competitors?
### I wondered about that scheme too........ most bizzare
contraption ever devised.... and those amps work just great with the
grids directly grnded to the chassis.. and a grid fuse installed..
plus glich/hv fuse etc. I'm sure Rube Goldberg and Muncy both
worked for Henry Radio at one time.



RICH SEZ.. A friend went the Henry booth at a Hamvention and
asked one of the Henry engineers why none of the Henry 3-500Z
amplifiers currently had 160m coverage. The reply: 1.8MHz is
below the 3-500Z's low- frequency cutoff.

### LOL. Joke right ??


Early Henry amplifiers had a problem welding the contacts of
the power contactor that was used to switch them on and off.
Instead of doing the obvious -- adding a step-start relay and 2
step-start resistors, Henry's solution was to install an uncheap
humungous power contactor with mercury-wetted contacts.

### You never install 2 x step start resistors..... it's total loop
resistance we are concerned with here. Just install one step
start resistor.. in one leg of the 240 line. I use a 25 ohm
unit... consisting of a pair of 50 ohm resistor's in parallel [50
w /100w each]. The paralleled approach offers redundancy...if one
ever opened... still got the 2nd one.. albeit 50 ohms. All thta's
neede is a SPST-DM contactor or SPST relay to sort out the one
step start resistor. Stick one per leg,, and you then need a
DPST relay/contactor to short it out.

### Mercury wetted contacts is another waste of time. Loads of
good contactor's out there. A standard contactor is just 2 sets
of contacts.. in series... PER POLE, so u end up with no arcing
when trying to open a load off. [u split the arc into two
simultaneous arcs = zero arc]. They are called DPDT-DM [double
make]. Regular contactor's have the distinct advantage that
their contacts are all easily field replaceable. I clean new ones
up... slop some "cool amp" silver plating compound on em... and
zero ohms guaranteed everytime. You can slop a tiny layer
of "conducto lube" [pure silver powder, suspended in grease, made
for moving/sliding contacts] on em as well..... results in 110 %
success every time.... last a long time. Too many stock
contacts don't quite result in zero ohms when pushing on em with
ur fingers.. really hard.

### My conclusion is Henty doesn't "get it" with some aspects of
their stuff. I have their 10 kw LP filter.... compact,
superbly designed... then they can't build a HV supply right.
Their resonant choke scheme looks good on paper.. then Henry ends
up using one bad HV xfmr maker after another after another. IMO...
dump the resonant choke scheme alltogether, install a hypersil C
core, and a heavy duty FWB [1 kv- 6A -400 A surge diodes are dirt
cheap] , and a large C input filter.... and step start. If ur
gonna stick a ton of extra weight in there... add it to the plate
xfmr... not a choke.





I would love to hear the reasoning and experiences
when they built up the prototype of this amp.
### They probably all dragged out their 1934 engineering books.




The direct-grounding camp all reports no problems since their
mod. and swearby that solution.

### Yeah, I swear by it.... esp after 40 e-mails from other SB-
220/221/TL-922 owners, who also swear by it. It's worth it
anyway... guranteed 22-25 watts LESS drive required. I have yet
to hear from any of those guys about parasitic problems either.
The guys with the TL-922's all said.. after directly grnding the
grids to the chassis.... they could all remove the after market
nichrome suppressor's... and re-install the stock kenwood
suppressor's..... rock stable.



RICH SEZ....The AL-82 and uses directly-grounded 3-500Z grid pins
and it has a well-deserved reputation for arcing open contacts on
its bandswitch.

### That's an apples and concrete comparison Rich. The AL-82 [2
x 3-500Z} is called the "firecracker" by the east coast crowd. The
AL-82 is an abortion..... along with it's little bastard child.. the
AL-80B. Both of em like to spit out flames... new right out of the
box..... and that's with just one good short coax.. from amp to
dummy load.... and using PTT... and keeping the loading heavy. The
layout is screwed up in both those amps. Notice the extra
bandswitch wafer's, and extra caps switched in across the bandswitch
itself..... it appears they have an internal resonance bandswitch
problem...esp on 17m.

### These guys just don't get it. You gotta use correct size
components to start with... and NO wire from any bandswitch
contacts..... just wide, silver plated strap for ALL
interconnections. I'd dump the PI-L nonsense, sky high loaded Q
circuits on high bands..... torroids on either the main or L-2
coil.... and other bizzare concepts like building a PI designed
to transform the tube's plate load Z.. down to 200 ohms... then using
a broadband torroid to transform the 200 ohms.. down to 50 ohms.
Diito with using PC boards to terminate tank coils on. RG-174
is to be avoided like the plague.

### The sad part is... then people will ask u to "fix" or re-
design "it".... and "It" is an ill conceived amp.... in a shoe
box.




The other three solutions speak for themselves, as there
must be thousands of 3-500Z's operating in the field with long
track records. The problems seem to increase when replacing Eimac
tubes with knock-offs.

RICH SEZ... Most of the grid-filament shorted tubes that I have high-
potted were Eimacs.

### All eimac 3=500Z's havee a MU= 130 Knock off's are all
MU=200.




It is obvious to me that some kind of grid fusing should be
included in any
modification one chooses.
RICH SEZ Indeed, Phil, unless one has a free supply of new 3-500Zs.
### agreed.... and this will set u back the cost of one high speed
3agc fuse...and one rear panel 3agc fuse holder..... what's that
come out to .... about $1.50 tops....... Ameritron could no
doubt get em for 20 cents... buying 100 K at a time.... then use
em in all their various amps..... cheap bastards..... ditto with
their RG-174 sub minature coax used in the tuned input to cathode.



I just wanted to pass along my experiences FWIW. Mods seem to be
in
order; the choice is up to you!
### The choice is.... stock, it's an accident waiting to happen...
so u either mod it now...... OR blow it up... THEN mod it.

Later.... Jim VE7RF



(((73)))
Phil Clements, K5PC






Yahoo! Groups Links




R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org
Re: w5uc's pi net spread sheet...deluxe.

pentalab
 

--- In ham_amplifiers@..., "Mike&#92;(W5UC&#92;) &
Kathy&#92;(K5MWH&#92;)" <w5uc@...> wrote:

Good Morning Noel & All:



I have started construction on a pair of GI-7b's for 6 meters, but
6 mtrs
cooled and 160 Mtrs got ready to come on for the winter. You can
see my
progress, or lack thereof on my web page.

>
73,

Mike, W5UC


#### then click on..."stuff" I tried the pi net for my tuned
inputs.... and it's slick.... since it does ALL bands at once. By
tweaking the Q in tiny increments... it spat out virtually
identical results to what we are using on both the 3000 A7 amp..
and the 6000A7 amp. Now here's the kicker..... the tube's input
Z may be a little lower than 50 ohms in my case.... and when
feeding with 50 ohm coax.... u will end up with a conjugate
match... so allow leeway [esp on 160m].. esp on the C2 cap closest
to cathode.

### another caveat with tuned inputs is... I ran 50 ohm coax
from the output of my vraiable tuned inputs... through a bird.. then
into dummy load..... could be tweaked dead flat on all bands. Trbl
was.... with exactly 200 w going in [had another bird on input
side], power out of tuned input , on low bands was around 195 w.
On 17-15... dropped to 160w ! Had to increase the L very
slightly.. reduce the C1 C2 caps a tiny bit.... then power out of
tuned inputs shot up to 193 watts.... and all is well. Point
is... don't run the Q too high.. run it high enough [on high bands
only] so power out of the tuned input on test jig just drops off...
then reduce the Q slightly [more L, less C1 + C2]

## Once output bird is removed.. and coax routed to tube's
cathode, etc.... and in operation on the air/dummy load... C1 + C2
caps are very close to the test set up..... just a little tweaking
on em resulted in ZERO watts reflected power... MAX grid current on
tube....and xcvr/ipa happy.

## Have not tried the pi spread sheets for big pi output... yet.
Dunno whether they factor in the stray L between anode and PI or
not.. as this has a huge effect... since any stray L b4 the PI
will drop/transform the plate load Z.. like a rock... which is
fine... but the PI has to be designed around a lower plate load Z.

all in all... superb sheet. Gotta spend more time with it. It
would be nice to have something that calculates the expected
peak/rms currents and rf voltages across all the components....
including the plate block cap, anode to chassis path, C1 C2...
and coil... + ant current. Then it makes it easier to size
stuff.

later.... Jim VE7RF
Re: chimney material

pentalab
 

--- In ham_amplifiers@..., "craxd" <craxd1@...> wrote:

Jim,

Did you ever try paper tubing for the chimneys? It's the same
kraft paper they use in transformer insulation. No hotter than
a tube gets with the blower running, it wont hurt anything.
This stuff is made in 10 foot lengths but can be bought
shorter through paper suppliers that make and sell cardboard
boxes, etc. A company named U-Line has a good selection of
large diameter tubing that would make a good chimney. A compamy
who makes the tubing is Precision Paper Tube. They make the
tubing used in inductors, etc.
### Have not tried this... yet. You would have to anchor it down
to the chassis... otherwise, it would obviously get blown through
the celing ! Since our local plastic shop has miles of thin
teflon sheeting.... I had huge sheets on hand... and actually
constructed a chimney, shaped like a cone, from teflon. The
advantage of this method is that the top of the cone is nice tight
fit around the tube... the base of the cone.. can be made any diam
you desire.... the bigger the base.... the bigger the holes u can
whack in the chassis.... and hence more airflow.

Another way is to fabricate one from fish paper, or the
blue-grey stuff used again as transformer insulation. It has
a clay added to it. It runs well as a chimney and one can roll
it up as a cone shape so its wider at the bottom as in some
chimneys.
### I'm into high level experimentation... up to a point. Between
soft x rays, heat, globs of RF, 8000Vdc, etc.... Teflon seemed like
a sure fire method/zero brainer. [u know it's gonna work ]



The last is to make a fiberglass chimney. One can buy the
fiberglass sheet and the resin from Sears and some
auto-body suppliers. Sears carries it in their boat
specialties catalog. You'd have to make a form for say a
cone shape out of teflon so the resin wont stick to it.
An aluminum form might work to using a release agent.
### agreed.... but I didn't want to make a major project out
of a chimney. The trbl with teflon sheeting, etc... is u gotta
anchor it to the chassis. At least with my original Straight up and
down stove pipe chimney..it was 1/4" thick teflon, and so
heavy, it's weight alone held it to the chassis. As noted b4...
it restricted the intake air too much.

### My conclusion is... either make a box around the tube.... OR a
cylinder... aprx 9.5" to 10" square or round... cover the top
with 3/16" thick teflon [with the 6.125" hole punched through] ,
and u are laughing. [for a 6000A7, smaller for a 3000A7 or a YC-
156] The box or cylinder around the tube can be made from
anything.... except metal. I had a metal chimney from RF parts
for the 3000A7 [ had a teflon top, with a 4.125" hole in the
teflon], it added exactly 10 pf of extra anode to chassis
C.... which was a disaster on the higher bands. Worked fine on the
lower bands.

### This latest one, currently under construction has the box
made from red micarta... and a 3/16" to 1/4" thick teflon
top. The box on all of these versions is anchored to the chassis,
with just 2 x screws from down below.

Tnx for the info Will. I note down alternatives... as I get e-
mail from guys all over the planet... who might not have ready
access to teflon... but do have access to stuff like kapton and
stiff xfmr paper.

Later.....Jim VE7RF

Best,

Will
Re: Grounding Grids on 3-500Z's

 

On Oct 26, 2006, at 2:11 PM, Phil Clements wrote:

I received a lot of interesting posts when I asked about repairing a grid
bypass choke fire on a customer's SB-220.

The most suggested fix I received was to strap all grid pins to chassis
ground, after removing all of the 200 pf bypass caps and the two 1 uh RF
chokes.

Another fix was to replace the 200 pf bypass caps with at least 500 pf
units, and replace the RF chokes with fusing resistors.
In my experiences, a suitable glitch-R in the HV+ helps prevent grid- filament shorts.

Absolutely nobody suggested returning the circuit to original factory specs.

On the far-end of the spectrum from direct-grounding of the grids has to be
the Henry 2K-4. No RF chokes are utilized, but there are 18- .003 mfd bypass
caps, 12- 10 ohm resistors, and a 250 ohm grid ma adjust potentiometer, all
hanging from grid pins to chassis! Grid pins (pin #4) of each tube are
strapped together. Pins 2 and 3 on each tube are strapped together, but not
strapped tube-to-tube. Also, Henry chose to use 2- 150 ohm resistors in
parallel with the coil on the parasitic suppressors.

The question of the day is why Henry chose a more expensive approach than
any of their competitors?
A friend went the Henry booth at a Hamvention and asked one of the Henry engineers why none of the Henry 3-500Z amplifiers currently had 160m coverage. The reply: 1.8MHz is below the 3-500Z's low- frequency cutoff.
Early Henry amplifiers had a problem welding the contacts of the power contactor that was used to switch them on and off. Instead of doing the obvious -- adding a step-start relay and 2 step-start resistors, Henry's solution was to install an uncheap humungous power contactor with mercury-wetted contacts.

I would love to hear the reasoning and experiences
when they built up the prototype of this amp.

The direct-grounding camp all reports no problems since their mod. and swear
by that solution.
The AL-82 and uses directly-grounded 3-500Z grid pins and it has a well-deserved reputation for arcing open contacts on its bandswitch.


The other three solutions speak for themselves, as there
must be thousands of 3-500Z's operating in the field with long track
records. The problems seem to increase when replacing Eimac tubes with
knock-offs.
Most of the grid-filament shorted tubes that I have high-potted were Eimacs.

It is obvious to me that some kind of grid fusing should be included in any
modification one chooses.
Indeed, Phil, unless one has a free supply of new 3-500Zs.

Using an RF choke (Heath, Kenwood, et al) for a
grid fuse can result in a hole burned in the grid, and a choke fire.
... and even a meltdown in the unfused LV xfmr (TL-922, SB-220) in the event that the unit has not been converted from factory stock V- cutoff bias to R-cutoff bias. .

I just wanted to pass along my experiences FWIW. Mods seem to be in order;
the choice is up to you!

(((73)))
Phil Clements, K5PC






Yahoo! Groups Links




R L Measures, AG6K, 805.386.3734
r@..., , rlm@..., www.somis.org
Re: TL922 transformer and other

FRANCIS CARCIA
 

Will, I agree.
When you design a transformer for 10 KG there is an oversized core or extra windings both of wich increase the resistance losses. This same transformer at 50 Hz. will be more efficient than on 60 Hz.?I did that once hoping for the best.
I would think it better to buy a transformer with 1.2X primary?voltage rating . I have a pair of UTC CG310s in the bottom of a rack running at 240 volts in. I've tried to run themon the 216 volt tap to get higher output voltage and noticed they warm up just sitting in stand by.
On the high tap they run stone cold. I get a bit more output voltage on the low tap but notice a real change in efficiency.
my class E power supply iron is on the?edge of saturation and run high mag. current. I actually added more?core material to bring it down. 4 transformers draw almost 1 amp just sitting.(40 watts of bleeder)?compare that to say a BC 610 plate transformer that runs under 200 ma.?fc

craxd wrote:

Francis,

If we took a transformer say designed to run at 10 kilogauss, but the
iron would run okay at 12 kilogauss, then dropped the frequency down
to 50 Hz, it would probably be okay since the flux density would rise
up to an acceptable amount at 12 kilogauss. However if we had one
designed around say 15 kilogauss and dropped the frequency, the
transformer could go into saturation and the current really shoot up
if it's max flux density was lower like say M-22 or M-27, etc. When
looking at the B-H curve for a type of iron, one supposed to pick a
spot just below the knee, to just maybe up on it a small amount. On
up the knee though is going into the saturation region, where the
higher the flux, magnetizing current raises rapidly, and
expotentially. If one could find one where the flux density was ran a
bit below the knee, and then try the lower frequency, it should just
raise up on the knee to where it's still acceptable. They do wind
some this way for heavy duty service, adding more iron than needed.
In reality though, one would still be using what would have been a 50
Hz transformer at 60 Hz though they spec it as a 60 Hz transformer.
The power capability would drop though I guess by 1.2 times. But,
since it was over-sized already like above, it would still be okay at
the projected power level, just derated to a different service
factor. The thing is, most off the shelf transformers are designed
right close to the edge for normal duty cycles. One would have to buy
one with a higher power rating to achieve this result.

They'll all draw some magnetizing current, but after coming into the
saturation region, it raises rapidly as compared to smaller increases
in flux density. The saturation region can be seen on a scope as the
waveform will become distorted. If the magnetizing current does
raise, it doesn't necessarily mean the core is saturated. It really
shows that the flux density has raised because of the lower
frequency. If it raised and the waveform is still normal, it should
be okay to run as long as the wire size will handle the increased
current. Of course we would be derating it anyhow by about the same
amount.

If so, one ought to be able to buy a transformer with about 1.2 times
the power rating needed to achieve the same result. This since the
only things that effect flux density is voltage, core area,
frequency, and the number of turns. That is as long as the iron will
handle the increase in flux with the voltage, number of turns, and
core area the same. The frequency being the only changing factor. One
fly in the ointment would be that most 50 Hz applications uses a
lower voltage.

If designing a 50 Hz to set in place of a 60 Hz exactly, and the iron
they used was like M-19, one could design the new one with M-6. It
will raise the flux density limit a good bit. However, when you bring
a different voltage into the equation along with lower frequency, I
don't know if it would work or not.

Best,

Will

--- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
wrote:
>
> Will,
> I lived it once and was unable to make the loss equal for both 50
and 60 Hz. I got close but the 50 Hz high line started to suck
current. frank wa1gfz
>
> craxd wrote:
> Francis,
>
> Yup, your right. I was going by the difference in the two formulas
> between 50 and 60 Hz. Both sets have a difference of 1.2. See below;
>
> For 60 Hz
>
> TPV = 4.85 / A
>
> A = 0.1725 x sq rt of P
>
> P = ( a / 0.1725 )^2
>
> --------------------------------
>
> For 50 Hz
>
> TPV = 5.82 / A (5.82 / 4.85 = 1.2)
>
> A = 0.207 x sq rt of P (0.207 / 0.1725 = 1.2)
>
> P = ( a / 0.207 )^2
>
> If you notice, the difference between each formula from 60 Hz to 50
> Hz is 1.2. That's why after I looked, I assumed both raised. The
TPV
> had to be changed to make it come out correctly. One can either
> adjust the number of turns or the core size to achieve the goal,
but
> not both together as it would be off (the formulas above have to
> though). I guess one could by splitting the difference, but the
> formulas above don't take that into account. When I did both and
> checked them with the long formulas, they came out even on the
turns.
> The resistance then would only raise over the extra wire length.
> Since the core area is 1.2 times greater, I'd say the wire length
> will be 1.2 times longer.
>
> So void what I said earlier, it's not correct. I'm glad you caught
> this as I'm sure not at myself today.
>
> Best,
>
> Will
>
> --- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
> wrote:
> >
> > Will, untrue all you need to do is make the core bigger to reduce
> the flux at 50 Hz. Volts per turn stay the same. Wire will be a bit
> longer due to bigger window. So bigger core makes more resistance
> when the 50 hz transformer is at 60 hz but core loss is very
slightly
> less.
> > Whenever you make the core bigger you can get away with lessturns
> of wire for the same flux density. Double the core area= 1/2 the
> turns for constant flux
> >
> > craxd wrote:
> > Actually everything goes up by a factor of 1.2. Not only
> does the
> > core have 1.2 times the iron, the turns per volt is 1.2 times
> higher.
> > Since the turns are higher, the resistance will go up 1.2 times
> > unless a larger diameter wire is used to drop it back down.
Whoever
> > designed the transformer should know this I would think, and
> account
> > for it so as to acchieve the same power output.
> >
> > Generally what is done is to use a larger laminate size and stack
> > them to get the right thickness. The larger lam size has larger
> > windows which allows a larger diameter wire to be used. This has
to
> > be done anyhow to hold the extra wire over the higher turns so it
> has
> > to be stepped up even larger to increase the wire diameter. If
the
> > turns are dropped to just accept the larger wire, the flux
density
> > and magnetizing current will raise. One could play with the lam
> > material here, and use one that operates at a higher flux
density,
> > but the cost will go up. Another alternative would be add more
iron
> > which would lower the flux density, but again, cost goes up.
> >
> > If one was in production, it would be best just about it to use a
> 50
> > Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
> Hz
> > users as it would run cooler with a lower flux density. This
would
> > make a one size fits all transformer so the chassis wouldn't have
> to
> > be modified between the two.
> >
> > Best,
> >
> > Will
> >
> > --- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
> > wrote:
> > >
> > > Lower frequency you need more primary turns so a higher tap to
> > reduce heating but this will reduce the output voltage due to
turns
> > ratio change, gfz
> > >
> > > pentalab > wrote: --- In
> > ham_amplifiers@yahoogroups.com, "Hsu" wrote:
> > > >
> > > > Thanks,Will
> > > > Could tell me the power rating of TL922 HV transformer?
> > > > Thanks again!
> > > > 73! Hsu
> > > > ----- Original Message -----
> > >
> > > #### HSU.... as far as I know.... from memeory... the plate
> > > xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
> > > plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
> > > CCS.
> > >
> > > #### In the case of the RL drake xfmr.... that rating is for 60
> > > hz only..... and like Will sez.... it MUST be de-rated for 50
> > > hz. Several VK/ZL's I have spoken too over the years have
> > > complained of over heating the RL drake xfmr, when run on 50
hz.
> > >
> > > ### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
> > > [1977] , it had primary taps for 100/120 200/240.... in Japan
> > > they use 100/200 V and 50 hz. So In that case, I'd assume
> > > the yaesu plate xfmr would run on 50 hz.
> > >
> > > ### IF the TL-922 xfmr has pri taps for 100/200v.... you can
> > > asume it will run ok on 50 hz. IF it only has taps for
> > > 120/240... then asume it's 60 hz only. It seems to me that
> > > the TL-922 is popular in the UK... and I believe they use 220 v
> 50
> > > hz.
> > >
> > > ### In normal operation... the TL-922 xfmr would be good for
> > > 600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb....
and
> > > maybe a little less on CW.
> > >
> > > ### I agree with Will. You can't go by weight alone. Case in
> > > point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
> > > [36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
> > > used in a C input filter.... and when running 1900w PEP output
> > > from the linear.
> > >
> > > ### In the case of the Hammond, it was a high reactance type,
> > > with a center tap, designed for tube rectifier's... and had a
> high
> > > 68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
> > > ohm DC sec... is made for a C input filter.. and is of the LOW
> > > reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
> > > resistance secondaries.
> > >
> > > ### These Peter Dahl hypersil C core plate xfmr's flat out
won't
> > > blow up, or overheat, doesn't matter what you do to em. They
are
> > > either the most underated things, or the greatest things since
> > > sliced bread... take ur pick.
> > >
> > > Later... Jim VE7RF
> > >
> >
>
Re: [??????????????] Re: TL922 transformer and otherr

FRANCIS CARCIA
 

Materials like kapton insulators are rated at 7000 volts / mil do a better job than a layer of paint. This is required when you build high voltage transformers. Low voltage you can rely on wire coating for insulating between layers. wa1gfz

Hsu wrote:

Thanks who reply about my questions.
My teacher in university, Prof. Chen, He often made some R xfmr,use 100VA iron for 180VA xfmr,
he do like this,primary and secondary must need apart.Use as thick as wire and no use paper as insulated paper in every tier.he use brush to besmear insulating paint in every tier.Thinck wire:low resitance, without insulating paper:
it possible to use thicker wire and the primary/ secondary beacame better heat sink( certainly, it need the insulating paper when the voltof secondary is too high, but he told the HV wire avaible now.he built many trans former like this, working great.
Hsu


----- Original Message -----
From: craxd
To: ham_amplifiers@yahoogroups.com
Sent: Friday, October 27, 2006 6:10 AM
Subject: [ham_amplifiers] Re: TL922 transformer and otherr


Francis,

If we took a transformer say designed to run at 10 kilogauss, but the
iron would run okay at 12 kilogauss, then dropped the frequency down
to 50 Hz, it would probably be okay since the flux density would rise
up to an acceptable amount at 12 kilogauss. However if we had one
designed around say 15 kilogauss and dropped the frequency, the
transformer could go into saturation and the current really shoot up
if it's max flux density was lower like say M-22 or M-27, etc. When
looking at the B-H curve for a type of iron, one supposed to pick a
spot just below the knee, to just maybe up on it a small amount. On
up the knee though is going into the saturation region, where the
higher the flux, magnetizing current raises rapidly, and
expotentially. If one could find one where the flux density was ran a
bit below the knee, and then try the lower frequency, it should just
raise up on the knee to where it's still acceptable. They do wind
some this way for heavy duty service, adding more iron than needed.
In reality though, one would still be using what would have been a 50
Hz transformer at 60 Hz though they spec it as a 60 Hz transformer.
The power capability would drop though I guess by 1.2 times. But,
since it was over-sized already like above, it would still be okay at
the projected power level, just derated to a different service
factor. The thing is, most off the shelf transformers are designed
right close to the edge for normal duty cycles. One would have to buy
one with a higher power rating to achieve this result.

They'll all draw some magnetizing current, but after coming into the
saturation region, it raises rapidly as compared to smaller increases
in flux density. The saturation region can be seen on a scope as the
waveform will become distorted. If the magnetizing current does
raise, it doesn't necessarily mean the core is saturated. It really
shows that the flux density has raised because of the lower
frequency. If it raised and the waveform is still normal, it should
be okay to run as long as the wire size will handle the increased
current. Of course we would be derating it anyhow by about the same
amount.

If so, one ought to be able to buy a transformer with about 1.2 times
the power rating needed to achieve the same result. This since the
only things that effect flux density is voltage, core area,
frequency, and the number of turns. That is as long as the iron will
handle the increase in flux with the voltage, number of turns, and
core area the same. The frequency being the only changing factor. One
fly in the ointment would be that most 50 Hz applications uses a
lower voltage.

If designing a 50 Hz to set in place of a 60 Hz exactly, and the iron
they used was like M-19, one could design the new one with M-6. It
will raise the flux density limit a good bit. However, when you bring
a different voltage into the equation along with lower frequency, I
don't know if it would work or not.

Best,

Will

--- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
wrote:
>
> Will,
> I lived it once and was unable to make the loss equal for both 50
and 60 Hz. I got close but the 50 Hz high line started to suck
current. frank wa1gfz
>
> craxd wrote:
> Francis,
>
> Yup, your right. I was going by the difference in the two formulas
> between 50 and 60 Hz. Both sets have a difference of 1.2. See below;
>
> For 60 Hz
>
> TPV = 4.85 / A
>
> A = 0.1725 x sq rt of P
>
> P = ( a / 0.1725 )^2
>
> --------------------------------
>
> For 50 Hz
>
> TPV = 5.82 / A (5.82 / 4.85 = 1.2)
>
> A = 0.207 x sq rt of P (0.207 / 0.1725 = 1.2)
>
> P = ( a / 0.207 )^2
>
> If you notice, the difference between each formula from 60 Hz to 50
> Hz is 1.2. That's why after I looked, I assumed both raised. The
TPV
> had to be changed to make it come out correctly. One can either
> adjust the number of turns or the core size to achieve the goal,
but
> not both together as it would be off (the formulas above have to
> though). I guess one could by splitting the difference, but the
> formulas above don't take that into account. When I did both and
> checked them with the long formulas, they came out even on the
turns.
> The resistance then would only raise over the extra wire length.
> Since the core area is 1.2 times greater, I'd say the wire length
> will be 1.2 times longer.
>
> So void what I said earlier, it's not correct. I'm glad you caught
> this as I'm sure not at myself today.
>
> Best,
>
> Will
>
> --- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
> wrote:
> >
> > Will, untrue all you need to do is make the core bigger to reduce
> the flux at 50 Hz. Volts per turn stay the same. Wire will be a bit
> longer due to bigger window. So bigger core makes more resistance
> when the 50 hz transformer is at 60 hz but core loss is very
slightly
> less.
> > Whenever you make the core bigger you can get away with lessturns
> of wire for the same flux density. Double the core area= 1/2 the
> turns for constant flux
> >
> > craxd wrote:
> > Actually everything goes up by a factor of 1.2. Not only
> does the
> > core have 1.2 times the iron, the turns per volt is 1.2 times
> higher.
> > Since the turns are higher, the resistance will go up 1.2 times
> > unless a larger diameter wire is used to drop it back down.
Whoever
> > designed the transformer should know this I would think, and
> account
> > for it so as to acchieve the same power output.
> >
> > Generally what is done is to use a larger laminate size and stack
> > them to get the right thickness. The larger lam size has larger
> > windows which allows a larger diameter wire to be used. This has
to
> > be done anyhow to hold the extra wire over the higher turns so it
> has
> > to be stepped up even larger to increase the wire diameter. If
the
> > turns are dropped to just accept the larger wire, the flux
density
> > and magnetizing current will raise. One could play with the lam
> > material here, and use one that operates at a higher flux
density,
> > but the cost will go up. Another alternative would be add more
iron
> > which would lower the flux density, but again, cost goes up.
> >
> > If one was in production, it would be best just about it to use a
> 50
> > Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
> Hz
> > users as it would run cooler with a lower flux density. This
would
> > make a one size fits all transformer so the chassis wouldn't have
> to
> > be modified between the two.
> >
> > Best,
> >
> > Will
> >
> > --- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
> > wrote:
> > >
> > > Lower frequency you need more primary turns so a higher tap to
> > reduce heating but this will reduce the output voltage due to
turns
> > ratio change, gfz
> > >
> > > pentalab > wrote: --- In
> > ham_amplifiers@yahoogroups.com, "Hsu" wrote:
> > > >
> > > > Thanks,Will
> > > > Could tell me the power rating of TL922 HV transformer?
> > > > Thanks again!
> > > > 73! Hsu
> > > > ----- Original Message -----
> > >
> > > #### HSU.... as far as I know.... from memeory... the plate
> > > xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
> > > plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
> > > CCS.
> > >
> > > #### In the case of the RL drake xfmr.... that rating is for 60
> > > hz only..... and like Will sez.... it MUST be de-rated for 50
> > > hz. Several VK/ZL's I have spoken too over the years have
> > > complained of over heating the RL drake xfmr, when run on 50
hz.
> > >
> > > ### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
> > > [1977] , it had primary taps for 100/120 200/240.... in Japan
> > > they use 100/200 V and 50 hz. So In that case, I'd assume
> > > the yaesu plate xfmr would run on 50 hz.
> > >
> > > ### IF the TL-922 xfmr has pri taps for 100/200v.... you can
> > > asume it will run ok on 50 hz. IF it only has taps for
> > > 120/240... then asume it's 60 hz only. It seems to me that
> > > the TL-922 is popular in the UK... and I believe they use 220 v
> 50
> > > hz.
> > >
> > > ### In normal operation... the TL-922 xfmr would be good for
> > > 600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb....
and
> > > maybe a little less on CW.
> > >
> > > ### I agree with Will. You can't go by weight alone. Case in
> > > point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
> > > [36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
> > > used in a C input filter.... and when running 1900w PEP output
> > > from the linear.
> > >
> > > ### In the case of the Hammond, it was a high reactance type,
> > > with a center tap, designed for tube rectifier's... and had a
> high
> > > 68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
> > > ohm DC sec... is made for a C input filter.. and is of the LOW
> > > reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
> > > resistance secondaries.
> > >
> > > ### These Peter Dahl hypersil C core plate xfmr's flat out
won't
> > > blow up, or overheat, doesn't matter what you do to em. They
are
> > > either the most underated things, or the greatest things since
> > > sliced bread... take ur pick.
> > >
> > > Later... Jim VE7RF
> > >
> >
>
Re: [??????????????] Re: TL922 transformer and otherr

Hsu
 

Thanks who reply about my questions.
My teacher in university, Prof. Chen, He often made some R xfmr,use 100VA iron for 180VA xfmr,
he do like this,primary and secondary must need apart.Use as thick as wire and no use paper as insulated paper in every tier.he use brush to besmear insulating paint in every tier.Thinck wire:low resitance, without insulating paper:
it possible to use thicker wire and the primary/ secondary beacame better heat sink( certainly, it need the insulating paper when the voltof secondary is too high, but he told the HV wire avaible now.he built many trans former like this, working great.
Hsu

----- Original Message -----
From: craxd
To: ham_amplifiers@...
Sent: Friday, October 27, 2006 6:10 AM
Subject: [ham_amplifiers] Re: TL922 transformer and otherr


Francis,

If we took a transformer say designed to run at 10 kilogauss, but the
iron would run okay at 12 kilogauss, then dropped the frequency down
to 50 Hz, it would probably be okay since the flux density would rise
up to an acceptable amount at 12 kilogauss. However if we had one
designed around say 15 kilogauss and dropped the frequency, the
transformer could go into saturation and the current really shoot up
if it's max flux density was lower like say M-22 or M-27, etc. When
looking at the B-H curve for a type of iron, one supposed to pick a
spot just below the knee, to just maybe up on it a small amount. On
up the knee though is going into the saturation region, where the
higher the flux, magnetizing current raises rapidly, and
expotentially. If one could find one where the flux density was ran a
bit below the knee, and then try the lower frequency, it should just
raise up on the knee to where it's still acceptable. They do wind
some this way for heavy duty service, adding more iron than needed.
In reality though, one would still be using what would have been a 50
Hz transformer at 60 Hz though they spec it as a 60 Hz transformer.
The power capability would drop though I guess by 1.2 times. But,
since it was over-sized already like above, it would still be okay at
the projected power level, just derated to a different service
factor. The thing is, most off the shelf transformers are designed
right close to the edge for normal duty cycles. One would have to buy
one with a higher power rating to achieve this result.

They'll all draw some magnetizing current, but after coming into the
saturation region, it raises rapidly as compared to smaller increases
in flux density. The saturation region can be seen on a scope as the
waveform will become distorted. If the magnetizing current does
raise, it doesn't necessarily mean the core is saturated. It really
shows that the flux density has raised because of the lower
frequency. If it raised and the waveform is still normal, it should
be okay to run as long as the wire size will handle the increased
current. Of course we would be derating it anyhow by about the same
amount.

If so, one ought to be able to buy a transformer with about 1.2 times
the power rating needed to achieve the same result. This since the
only things that effect flux density is voltage, core area,
frequency, and the number of turns. That is as long as the iron will
handle the increase in flux with the voltage, number of turns, and
core area the same. The frequency being the only changing factor. One
fly in the ointment would be that most 50 Hz applications uses a
lower voltage.

If designing a 50 Hz to set in place of a 60 Hz exactly, and the iron
they used was like M-19, one could design the new one with M-6. It
will raise the flux density limit a good bit. However, when you bring
a different voltage into the equation along with lower frequency, I
don't know if it would work or not.

Best,

Will

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@...>
wrote:

Will,
I lived it once and was unable to make the loss equal for both 50
and 60 Hz. I got close but the 50 Hz high line started to suck
current. frank wa1gfz

craxd <craxd1@...> wrote:
Francis,

Yup, your right. I was going by the difference in the two formulas
between 50 and 60 Hz. Both sets have a difference of 1.2. See below;

For 60 Hz

TPV = 4.85 / A

A = 0.1725 x sq rt of P

P = ( a / 0.1725 )^2

--------------------------------

For 50 Hz

TPV = 5.82 / A (5.82 / 4.85 = 1.2)

A = 0.207 x sq rt of P (0.207 / 0.1725 = 1.2)

P = ( a / 0.207 )^2

If you notice, the difference between each formula from 60 Hz to 50
Hz is 1.2. That's why after I looked, I assumed both raised. The
TPV
had to be changed to make it come out correctly. One can either
adjust the number of turns or the core size to achieve the goal,
but
not both together as it would be off (the formulas above have to
though). I guess one could by splitting the difference, but the
formulas above don't take that into account. When I did both and
checked them with the long formulas, they came out even on the
turns.
The resistance then would only raise over the extra wire length.
Since the core area is 1.2 times greater, I'd say the wire length
will be 1.2 times longer.

So void what I said earlier, it's not correct. I'm glad you caught
this as I'm sure not at myself today.

Best,

Will

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@>
wrote:

Will, untrue all you need to do is make the core bigger to reduce
the flux at 50 Hz. Volts per turn stay the same. Wire will be a bit
longer due to bigger window. So bigger core makes more resistance
when the 50 hz transformer is at 60 hz but core loss is very
slightly
less.
Whenever you make the core bigger you can get away with lessturns
of wire for the same flux density. Double the core area= 1/2 the
turns for constant flux

craxd <craxd1@> wrote:
Actually everything goes up by a factor of 1.2. Not only
does the
core have 1.2 times the iron, the turns per volt is 1.2 times
higher.
Since the turns are higher, the resistance will go up 1.2 times
unless a larger diameter wire is used to drop it back down.
Whoever
designed the transformer should know this I would think, and
account
for it so as to acchieve the same power output.

Generally what is done is to use a larger laminate size and stack
them to get the right thickness. The larger lam size has larger
windows which allows a larger diameter wire to be used. This has
to
be done anyhow to hold the extra wire over the higher turns so it
has
to be stepped up even larger to increase the wire diameter. If
the
turns are dropped to just accept the larger wire, the flux
density
and magnetizing current will raise. One could play with the lam
material here, and use one that operates at a higher flux
density,
but the cost will go up. Another alternative would be add more
iron
which would lower the flux density, but again, cost goes up.

If one was in production, it would be best just about it to use a
50
Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
Hz
users as it would run cooler with a lower flux density. This
would
make a one size fits all transformer so the chassis wouldn't have
to
be modified between the two.

Best,

Will

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@>
wrote:

Lower frequency you need more primary turns so a higher tap to
reduce heating but this will reduce the output voltage due to
turns
ratio change, gfz

pentalab <jim.thomson@> wrote: --- In
ham_amplifiers@..., "Hsu" <Jbenson@> wrote:

Thanks,Will
Could tell me the power rating of TL922 HV transformer?
Thanks again!
73! Hsu
----- Original Message -----
#### HSU.... as far as I know.... from memeory... the plate
xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
CCS.

#### In the case of the RL drake xfmr.... that rating is for 60
hz only..... and like Will sez.... it MUST be de-rated for 50
hz. Several VK/ZL's I have spoken too over the years have
complained of over heating the RL drake xfmr, when run on 50
hz.

### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
[1977] , it had primary taps for 100/120 200/240.... in Japan
they use 100/200 V and 50 hz. So In that case, I'd assume
the yaesu plate xfmr would run on 50 hz.

### IF the TL-922 xfmr has pri taps for 100/200v.... you can
asume it will run ok on 50 hz. IF it only has taps for
120/240... then asume it's 60 hz only. It seems to me that
the TL-922 is popular in the UK... and I believe they use 220 v
50
hz.

### In normal operation... the TL-922 xfmr would be good for
600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb....
and
maybe a little less on CW.

### I agree with Will. You can't go by weight alone. Case in
point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
[36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
used in a C input filter.... and when running 1900w PEP output
from the linear.

### In the case of the Hammond, it was a high reactance type,
with a center tap, designed for tube rectifier's... and had a
high
68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
ohm DC sec... is made for a C input filter.. and is of the LOW
reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
resistance secondaries.

### These Peter Dahl hypersil C core plate xfmr's flat out
won't
blow up, or overheat, doesn't matter what you do to em. They
are
either the most underated things, or the greatest things since
sliced bread... take ur pick.

Later... Jim VE7RF
Subject Change

Tony King - W4ZT
 

Gents,

It would do us all good if we tried to make our subject line match what we talk about in our postings. Otherwise, the thread is completely disjointed and very difficult to follow. When the subject line matches the discussion it is a pleasure to read.

Thanks!

73, Tony W4ZT
Re: TL922 transformer and other

craxd
 

Francis,

If we took a transformer say designed to run at 10 kilogauss, but the
iron would run okay at 12 kilogauss, then dropped the frequency down
to 50 Hz, it would probably be okay since the flux density would rise
up to an acceptable amount at 12 kilogauss. However if we had one
designed around say 15 kilogauss and dropped the frequency, the
transformer could go into saturation and the current really shoot up
if it's max flux density was lower like say M-22 or M-27, etc. When
looking at the B-H curve for a type of iron, one supposed to pick a
spot just below the knee, to just maybe up on it a small amount. On
up the knee though is going into the saturation region, where the
higher the flux, magnetizing current raises rapidly, and
expotentially. If one could find one where the flux density was ran a
bit below the knee, and then try the lower frequency, it should just
raise up on the knee to where it's still acceptable. They do wind
some this way for heavy duty service, adding more iron than needed.
In reality though, one would still be using what would have been a 50
Hz transformer at 60 Hz though they spec it as a 60 Hz transformer.
The power capability would drop though I guess by 1.2 times. But,
since it was over-sized already like above, it would still be okay at
the projected power level, just derated to a different service
factor. The thing is, most off the shelf transformers are designed
right close to the edge for normal duty cycles. One would have to buy
one with a higher power rating to achieve this result.

They'll all draw some magnetizing current, but after coming into the
saturation region, it raises rapidly as compared to smaller increases
in flux density. The saturation region can be seen on a scope as the
waveform will become distorted. If the magnetizing current does
raise, it doesn't necessarily mean the core is saturated. It really
shows that the flux density has raised because of the lower
frequency. If it raised and the waveform is still normal, it should
be okay to run as long as the wire size will handle the increased
current. Of course we would be derating it anyhow by about the same
amount.

If so, one ought to be able to buy a transformer with about 1.2 times
the power rating needed to achieve the same result. This since the
only things that effect flux density is voltage, core area,
frequency, and the number of turns. That is as long as the iron will
handle the increase in flux with the voltage, number of turns, and
core area the same. The frequency being the only changing factor. One
fly in the ointment would be that most 50 Hz applications uses a
lower voltage.

If designing a 50 Hz to set in place of a 60 Hz exactly, and the iron
they used was like M-19, one could design the new one with M-6. It
will raise the flux density limit a good bit. However, when you bring
a different voltage into the equation along with lower frequency, I
don't know if it would work or not.

Best,

Will


--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@...>
wrote:

Will,
I lived it once and was unable to make the loss equal for both 50
and 60 Hz. I got close but the 50 Hz high line started to suck
current. frank wa1gfz

craxd <craxd1@...> wrote:
Francis,

Yup, your right. I was going by the difference in the two formulas
between 50 and 60 Hz. Both sets have a difference of 1.2. See below;

For 60 Hz

TPV = 4.85 / A

A = 0.1725 x sq rt of P

P = ( a / 0.1725 )^2

--------------------------------

For 50 Hz

TPV = 5.82 / A (5.82 / 4.85 = 1.2)

A = 0.207 x sq rt of P (0.207 / 0.1725 = 1.2)

P = ( a / 0.207 )^2

If you notice, the difference between each formula from 60 Hz to 50
Hz is 1.2. That's why after I looked, I assumed both raised. The
TPV
had to be changed to make it come out correctly. One can either
adjust the number of turns or the core size to achieve the goal,
but
not both together as it would be off (the formulas above have to
though). I guess one could by splitting the difference, but the
formulas above don't take that into account. When I did both and
checked them with the long formulas, they came out even on the
turns.
The resistance then would only raise over the extra wire length.
Since the core area is 1.2 times greater, I'd say the wire length
will be 1.2 times longer.

So void what I said earlier, it's not correct. I'm glad you caught
this as I'm sure not at myself today.

Best,

Will

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@>
wrote:

Will, untrue all you need to do is make the core bigger to reduce
the flux at 50 Hz. Volts per turn stay the same. Wire will be a bit
longer due to bigger window. So bigger core makes more resistance
when the 50 hz transformer is at 60 hz but core loss is very
slightly
less.
Whenever you make the core bigger you can get away with lessturns
of wire for the same flux density. Double the core area= 1/2 the
turns for constant flux

craxd <craxd1@> wrote:
Actually everything goes up by a factor of 1.2. Not only
does the
core have 1.2 times the iron, the turns per volt is 1.2 times
higher.
Since the turns are higher, the resistance will go up 1.2 times
unless a larger diameter wire is used to drop it back down.
Whoever
designed the transformer should know this I would think, and
account
for it so as to acchieve the same power output.

Generally what is done is to use a larger laminate size and stack
them to get the right thickness. The larger lam size has larger
windows which allows a larger diameter wire to be used. This has
to
be done anyhow to hold the extra wire over the higher turns so it
has
to be stepped up even larger to increase the wire diameter. If
the
turns are dropped to just accept the larger wire, the flux
density
and magnetizing current will raise. One could play with the lam
material here, and use one that operates at a higher flux
density,
but the cost will go up. Another alternative would be add more
iron
which would lower the flux density, but again, cost goes up.

If one was in production, it would be best just about it to use a
50
Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
Hz
users as it would run cooler with a lower flux density. This
would
make a one size fits all transformer so the chassis wouldn't have
to
be modified between the two.

Best,

Will

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@>
wrote:

Lower frequency you need more primary turns so a higher tap to
reduce heating but this will reduce the output voltage due to
turns
ratio change, gfz

pentalab <jim.thomson@> wrote: --- In
ham_amplifiers@..., "Hsu" <Jbenson@> wrote:

Thanks,Will
Could tell me the power rating of TL922 HV transformer?
Thanks again!
73! Hsu
----- Original Message -----
#### HSU.... as far as I know.... from memeory... the plate
xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
CCS.

#### In the case of the RL drake xfmr.... that rating is for 60
hz only..... and like Will sez.... it MUST be de-rated for 50
hz. Several VK/ZL's I have spoken too over the years have
complained of over heating the RL drake xfmr, when run on 50
hz.

### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
[1977] , it had primary taps for 100/120 200/240.... in Japan
they use 100/200 V and 50 hz. So In that case, I'd assume
the yaesu plate xfmr would run on 50 hz.

### IF the TL-922 xfmr has pri taps for 100/200v.... you can
asume it will run ok on 50 hz. IF it only has taps for
120/240... then asume it's 60 hz only. It seems to me that
the TL-922 is popular in the UK... and I believe they use 220 v
50
hz.

### In normal operation... the TL-922 xfmr would be good for
600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb....
and
maybe a little less on CW.

### I agree with Will. You can't go by weight alone. Case in
point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
[36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
used in a C input filter.... and when running 1900w PEP output
from the linear.

### In the case of the Hammond, it was a high reactance type,
with a center tap, designed for tube rectifier's... and had a
high
68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
ohm DC sec... is made for a C input filter.. and is of the LOW
reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
resistance secondaries.

### These Peter Dahl hypersil C core plate xfmr's flat out
won't
blow up, or overheat, doesn't matter what you do to em. They
are
either the most underated things, or the greatest things since
sliced bread... take ur pick.

Later... Jim VE7RF
Grounding Grids on 3-500Z's

Phil Clements
 

I received a lot of interesting posts when I asked about repairing a grid
bypass choke fire on a customer's SB-220.

The most suggested fix I received was to strap all grid pins to chassis
ground, after removing all of the 200 pf bypass caps and the two 1 uh RF
chokes.

Another fix was to replace the 200 pf bypass caps with at least 500 pf
units, and replace the RF chokes with fusing resistors.

Absolutely nobody suggested returning the circuit to original factory specs.

On the far-end of the spectrum from direct-grounding of the grids has to be
the Henry 2K-4. No RF chokes are utilized, but there are 18- .003 mfd bypass
caps, 12- 10 ohm resistors, and a 250 ohm grid ma adjust potentiometer, all
hanging from grid pins to chassis! Grid pins (pin #4) of each tube are
strapped together. Pins 2 and 3 on each tube are strapped together, but not
strapped tube-to-tube. Also, Henry chose to use 2- 150 ohm resistors in
parallel with the coil on the parasitic suppressors.

The question of the day is why Henry chose a more expensive approach than
any of their competitors? I would love to hear the reasoning and experiences
when they built up the prototype of this amp.

The direct-grounding camp all reports no problems since their mod. and swear
by that solution. The other three solutions speak for themselves, as there
must be thousands of 3-500Z's operating in the field with long track
records. The problems seem to increase when replacing Eimac tubes with
knock-offs.

It is obvious to me that some kind of grid fusing should be included in any
modification one chooses. Using an RF choke (Heath, Kenwood, et al) for a
grid fuse can result in a hole burned in the grid, and a choke fire.

I just wanted to pass along my experiences FWIW. Mods seem to be in order;
the choice is up to you!

(((73)))
Phil Clements, K5PC
Re: TL922 transformer and other

FRANCIS CARCIA
 

Will,
I lived it once and was unable to make the loss equal for both 50 and 60 Hz.?I got close but the 50 Hz high line started to suck current. frank wa1gfz?

craxd wrote:

Francis,

Yup, your right. I was going by the difference in the two formulas
between 50 and 60 Hz. Both sets have a difference of 1.2. See below;

For 60 Hz

TPV = 4.85 / A

A = 0.1725 x sq rt of P

P = ( a / 0.1725 )^2

--------------------------------

For 50 Hz

TPV = 5.82 / A (5.82 / 4.85 = 1.2)

A = 0.207 x sq rt of P (0.207 / 0.1725 = 1.2)

P = ( a / 0.207 )^2

If you notice, the difference between each formula from 60 Hz to 50
Hz is 1.2. That's why after I looked, I assumed both raised. The TPV
had to be changed to make it come out correctly. One can either
adjust the number of turns or the core size to achieve the goal, but
not both together as it would be off (the formulas above have to
though). I guess one could by splitting the difference, but the
formulas above don't take that into account. When I did both and
checked them with the long formulas, they came out even on the turns.
The resistance then would only raise over the extra wire length.
Since the core area is 1.2 times greater, I'd say the wire length
will be 1.2 times longer.

So void what I said earlier, it's not correct. I'm glad you caught
this as I'm sure not at myself today.

Best,

Will

--- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
wrote:
>
> Will, untrue all you need to do is make the core bigger to reduce
the flux at 50 Hz. Volts per turn stay the same. Wire will be a bit
longer due to bigger window. So bigger core makes more resistance
when the 50 hz transformer is at 60 hz but core loss is very slightly
less.
> Whenever you make the core bigger you can get away with lessturns
of wire for the same flux density. Double the core area= 1/2 the
turns for constant flux
>
> craxd wrote:
> Actually everything goes up by a factor of 1.2. Not only
does the
> core have 1.2 times the iron, the turns per volt is 1.2 times
higher.
> Since the turns are higher, the resistance will go up 1.2 times
> unless a larger diameter wire is used to drop it back down. Whoever
> designed the transformer should know this I would think, and
account
> for it so as to acchieve the same power output.
>
> Generally what is done is to use a larger laminate size and stack
> them to get the right thickness. The larger lam size has larger
> windows which allows a larger diameter wire to be used. This has to
> be done anyhow to hold the extra wire over the higher turns so it
has
> to be stepped up even larger to increase the wire diameter. If the
> turns are dropped to just accept the larger wire, the flux density
> and magnetizing current will raise. One could play with the lam
> material here, and use one that operates at a higher flux density,
> but the cost will go up. Another alternative would be add more iron
> which would lower the flux density, but again, cost goes up.
>
> If one was in production, it would be best just about it to use a
50
> Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
Hz
> users as it would run cooler with a lower flux density. This would
> make a one size fits all transformer so the chassis wouldn't have
to
> be modified between the two.
>
> Best,
>
> Will
>
> --- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
> wrote:
> >
> > Lower frequency you need more primary turns so a higher tap to
> reduce heating but this will reduce the output voltage due to turns
> ratio change, gfz
> >
> > pentalab > wrote: --- In
> ham_amplifiers@yahoogroups.com, "Hsu" wrote:
> > >
> > > Thanks,Will
> > > Could tell me the power rating of TL922 HV transformer?
> > > Thanks again!
> > > 73! Hsu
> > > ----- Original Message -----
> >
> > #### HSU.... as far as I know.... from memeory... the plate
> > xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
> > plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
> > CCS.
> >
> > #### In the case of the RL drake xfmr.... that rating is for 60
> > hz only..... and like Will sez.... it MUST be de-rated for 50
> > hz. Several VK/ZL's I have spoken too over the years have
> > complained of over heating the RL drake xfmr, when run on 50 hz.
> >
> > ### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
> > [1977] , it had primary taps for 100/120 200/240.... in Japan
> > they use 100/200 V and 50 hz. So In that case, I'd assume
> > the yaesu plate xfmr would run on 50 hz.
> >
> > ### IF the TL-922 xfmr has pri taps for 100/200v.... you can
> > asume it will run ok on 50 hz. IF it only has taps for
> > 120/240... then asume it's 60 hz only. It seems to me that
> > the TL-922 is popular in the UK... and I believe they use 220 v
50
> > hz.
> >
> > ### In normal operation... the TL-922 xfmr would be good for
> > 600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb.... and
> > maybe a little less on CW.
> >
> > ### I agree with Will. You can't go by weight alone. Case in
> > point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
> > [36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
> > used in a C input filter.... and when running 1900w PEP output
> > from the linear.
> >
> > ### In the case of the Hammond, it was a high reactance type,
> > with a center tap, designed for tube rectifier's... and had a
high
> > 68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
> > ohm DC sec... is made for a C input filter.. and is of the LOW
> > reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
> > resistance secondaries.
> >
> > ### These Peter Dahl hypersil C core plate xfmr's flat out won't
> > blow up, or overheat, doesn't matter what you do to em. They are
> > either the most underated things, or the greatest things since
> > sliced bread... take ur pick.
> >
> > Later... Jim VE7RF
> >
>
Re: TL922 transformer and other

craxd
 

Francis,

Yup, your right. I was going by the difference in the two formulas
between 50 and 60 Hz. Both sets have a difference of 1.2. See below;

For 60 Hz

TPV = 4.85 / A

A = 0.1725 x sq rt of P

P = ( a / 0.1725 )^2

--------------------------------

For 50 Hz

TPV = 5.82 / A (5.82 / 4.85 = 1.2)

A = 0.207 x sq rt of P (0.207 / 0.1725 = 1.2)

P = ( a / 0.207 )^2

If you notice, the difference between each formula from 60 Hz to 50
Hz is 1.2. That's why after I looked, I assumed both raised. The TPV
had to be changed to make it come out correctly. One can either
adjust the number of turns or the core size to achieve the goal, but
not both together as it would be off (the formulas above have to
though). I guess one could by splitting the difference, but the
formulas above don't take that into account. When I did both and
checked them with the long formulas, they came out even on the turns.
The resistance then would only raise over the extra wire length.
Since the core area is 1.2 times greater, I'd say the wire length
will be 1.2 times longer.

So void what I said earlier, it's not correct. I'm glad you caught
this as I'm sure not at myself today.

Best,

Will

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@...>
wrote:

Will, untrue all you need to do is make the core bigger to reduce
the flux at 50 Hz. Volts per turn stay the same. Wire will be a bit
longer due to bigger window. So bigger core makes more resistance
when the 50 hz transformer is at 60 hz but core loss is very slightly
less.
Whenever you make the core bigger you can get away with lessturns
of wire for the same flux density. Double the core area= 1/2 the
turns for constant flux

craxd <craxd1@...> wrote:
Actually everything goes up by a factor of 1.2. Not only
does the
core have 1.2 times the iron, the turns per volt is 1.2 times
higher.
Since the turns are higher, the resistance will go up 1.2 times
unless a larger diameter wire is used to drop it back down. Whoever
designed the transformer should know this I would think, and
account
for it so as to acchieve the same power output.

Generally what is done is to use a larger laminate size and stack
them to get the right thickness. The larger lam size has larger
windows which allows a larger diameter wire to be used. This has to
be done anyhow to hold the extra wire over the higher turns so it
has
to be stepped up even larger to increase the wire diameter. If the
turns are dropped to just accept the larger wire, the flux density
and magnetizing current will raise. One could play with the lam
material here, and use one that operates at a higher flux density,
but the cost will go up. Another alternative would be add more iron
which would lower the flux density, but again, cost goes up.

If one was in production, it would be best just about it to use a
50
Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
Hz
users as it would run cooler with a lower flux density. This would
make a one size fits all transformer so the chassis wouldn't have
to
be modified between the two.

Best,

Will

--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@>
wrote:

Lower frequency you need more primary turns so a higher tap to
reduce heating but this will reduce the output voltage due to turns
ratio change, gfz

pentalab <jim.thomson@> wrote: --- In
ham_amplifiers@..., "Hsu" <Jbenson@> wrote:

Thanks,Will
Could tell me the power rating of TL922 HV transformer?
Thanks again!
73! Hsu
----- Original Message -----
#### HSU.... as far as I know.... from memeory... the plate
xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
CCS.

#### In the case of the RL drake xfmr.... that rating is for 60
hz only..... and like Will sez.... it MUST be de-rated for 50
hz. Several VK/ZL's I have spoken too over the years have
complained of over heating the RL drake xfmr, when run on 50 hz.

### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
[1977] , it had primary taps for 100/120 200/240.... in Japan
they use 100/200 V and 50 hz. So In that case, I'd assume
the yaesu plate xfmr would run on 50 hz.

### IF the TL-922 xfmr has pri taps for 100/200v.... you can
asume it will run ok on 50 hz. IF it only has taps for
120/240... then asume it's 60 hz only. It seems to me that
the TL-922 is popular in the UK... and I believe they use 220 v
50
hz.

### In normal operation... the TL-922 xfmr would be good for
600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb.... and
maybe a little less on CW.

### I agree with Will. You can't go by weight alone. Case in
point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
[36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
used in a C input filter.... and when running 1900w PEP output
from the linear.

### In the case of the Hammond, it was a high reactance type,
with a center tap, designed for tube rectifier's... and had a
high
68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
ohm DC sec... is made for a C input filter.. and is of the LOW
reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
resistance secondaries.

### These Peter Dahl hypersil C core plate xfmr's flat out won't
blow up, or overheat, doesn't matter what you do to em. They are
either the most underated things, or the greatest things since
sliced bread... take ur pick.

Later... Jim VE7RF
Re: TL922 transformer and 50 Hz formulas

craxd
 

I forgot about Hsu being overseas. He would have a 50 Hz transformer
and the formula I showed was for 60 Hz at 12 kilogauss. The one for
50 Hz is;


TPV = 5.82 / a

a = 0.206 x sq rt of P

P = ( a / 0.206 )^2

a = Core area in square inches
TPV = Turns per volt
P = Power in Volt Amperes or Watts if load is resistive.

Sorry about that. I use 60 Hz so much I forget talking about 50 Hz
all together.

Best,

Will


--- In ham_amplifiers@..., "craxd" <craxd1@...> wrote:

Actually everything goes up by a factor of 1.2. Not only does the
core have 1.2 times the iron, the turns per volt is 1.2 times
higher.
Since the turns are higher, the resistance will go up 1.2 times
unless a larger diameter wire is used to drop it back down. Whoever
designed the transformer should know this I would think, and
account
for it so as to acchieve the same power output.

Generally what is done is to use a larger laminate size and stack
them to get the right thickness. The larger lam size has larger
windows which allows a larger diameter wire to be used. This has to
be done anyhow to hold the extra wire over the higher turns so it
has
to be stepped up even larger to increase the wire diameter. If the
turns are dropped to just accept the larger wire, the flux density
and magnetizing current will raise. One could play with the lam
material here, and use one that operates at a higher flux density,
but the cost will go up. Another alternative would be add more iron
which would lower the flux density, but again, cost goes up.

If one was in production, it would be best just about it to use a
50
Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60
Hz
users as it would run cooler with a lower flux density. This would
make a one size fits all transformer so the chassis wouldn't have
to
be modified between the two.

Best,

Will



--- In ham_amplifiers@..., FRANCIS CARCIA <carcia@>
wrote:

Lower frequency you need more primary turns so a higher tap to
reduce heating but this will reduce the output voltage due to turns
ratio change, gfz

pentalab <jim.thomson@> wrote: --- In
ham_amplifiers@..., "Hsu" <Jbenson@> wrote:

Thanks,Will
Could tell me the power rating of TL922 HV transformer?
Thanks again!
73! Hsu
----- Original Message -----
#### HSU.... as far as I know.... from memeory... the plate
xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
CCS.

#### In the case of the RL drake xfmr.... that rating is for 60
hz only..... and like Will sez.... it MUST be de-rated for 50
hz. Several VK/ZL's I have spoken too over the years have
complained of over heating the RL drake xfmr, when run on 50 hz.

### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
[1977] , it had primary taps for 100/120 200/240.... in Japan
they use 100/200 V and 50 hz. So In that case, I'd assume
the yaesu plate xfmr would run on 50 hz.

### IF the TL-922 xfmr has pri taps for 100/200v.... you can
asume it will run ok on 50 hz. IF it only has taps for
120/240... then asume it's 60 hz only. It seems to me that
the TL-922 is popular in the UK... and I believe they use 220 v
50
hz.

### In normal operation... the TL-922 xfmr would be good for
600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb.... and
maybe a little less on CW.

### I agree with Will. You can't go by weight alone. Case in
point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
[36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
used in a C input filter.... and when running 1900w PEP output
from the linear.

### In the case of the Hammond, it was a high reactance type,
with a center tap, designed for tube rectifier's... and had a
high
68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
ohm DC sec... is made for a C input filter.. and is of the LOW
reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
resistance secondaries.

### These Peter Dahl hypersil C core plate xfmr's flat out won't
blow up, or overheat, doesn't matter what you do to em. They are
either the most underated things, or the greatest things since
sliced bread... take ur pick.

Later... Jim VE7RF
Re: TL922 transformer and other

FRANCIS CARCIA
 

Will, untrue all you need to do is make the core bigger to reduce the flux at 50 Hz. Volts per turn stay the same. Wire will be a bit longer due to bigger window. So bigger core makes more resistance when the 50 hz transformer is at 60 hz but core loss is very slightly less.
Whenever you make the core bigger you can get away with lessturns of?wire for the same flux density. Double the core area=?1/2 the turns for constant flux

craxd wrote:

Actually everything goes up by a factor of 1.2. Not only does the
core have 1.2 times the iron, the turns per volt is 1.2 times higher.
Since the turns are higher, the resistance will go up 1.2 times
unless a larger diameter wire is used to drop it back down. Whoever
designed the transformer should know this I would think, and account
for it so as to acchieve the same power output.

Generally what is done is to use a larger laminate size and stack
them to get the right thickness. The larger lam size has larger
windows which allows a larger diameter wire to be used. This has to
be done anyhow to hold the extra wire over the higher turns so it has
to be stepped up even larger to increase the wire diameter. If the
turns are dropped to just accept the larger wire, the flux density
and magnetizing current will raise. One could play with the lam
material here, and use one that operates at a higher flux density,
but the cost will go up. Another alternative would be add more iron
which would lower the flux density, but again, cost goes up.

If one was in production, it would be best just about it to use a 50
Hz transformer for both 50 Hz and 60 Hz. The plus would be for 60 Hz
users as it would run cooler with a lower flux density. This would
make a one size fits all transformer so the chassis wouldn't have to
be modified between the two.

Best,

Will

--- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
wrote:
>
> Lower frequency you need more primary turns so a higher tap to
reduce heating but this will reduce the output voltage due to turns
ratio change, gfz
>
> pentalab ...> wrote: --- In
ham_amplifiers@yahoogroups.com, "Hsu" wrote:
> >
> > Thanks,Will
> > Could tell me the power rating of TL922 HV transformer?
> > Thanks again!
> > 73! Hsu
> > ----- Original Message -----
>
> #### HSU.... as far as I know.... from memeory... the plate
> xfmr in a TL-922 is rated at aprx 1.2 KVA CCS. The RL Drake
> plate xfmr, used in the L4/L4-B/ L-7 is also rated at 1.2 KVA
> CCS.
>
> #### In the case of the RL drake xfmr.... that rating is for 60
> hz only..... and like Will sez.... it MUST be de-rated for 50
> hz. Several VK/ZL's I have spoken too over the years have
> complained of over heating the RL drake xfmr, when run on 50 hz.
>
> ### Dunno about the TL-922 xfmr. On my old yaesu FL-2100 B
> [1977] , it had primary taps for 100/120 200/240.... in Japan
> they use 100/200 V and 50 hz. So In that case, I'd assume
> the yaesu plate xfmr would run on 50 hz.
>
> ### IF the TL-922 xfmr has pri taps for 100/200v.... you can
> asume it will run ok on 50 hz. IF it only has taps for
> 120/240... then asume it's 60 hz only. It seems to me that
> the TL-922 is popular in the UK... and I believe they use 220 v 50
> hz.
>
> ### In normal operation... the TL-922 xfmr would be good for
> 600 w output RTTY/ FM CCS..... and 1200 w out pep on ssb.... and
> maybe a little less on CW.
>
> ### I agree with Will. You can't go by weight alone. Case in
> point, the Hammond 795 series plate xfmr's weigh in at 80 lbs
> [36 kg] , are rated for 2.2 kva CCS.... and run VERY hot when
> used in a C input filter.... and when running 1900w PEP output
> from the linear.
>
> ### In the case of the Hammond, it was a high reactance type,
> with a center tap, designed for tube rectifier's... and had a high
> 68 ohm sec DC resistance. The drake L4B plate xfmr has a 10
> ohm DC sec... is made for a C input filter.. and is of the LOW
> reatance type.... the TL-922 and the SB-220 both have 10 ohm dc
> resistance secondaries.
>
> ### These Peter Dahl hypersil C core plate xfmr's flat out won't
> blow up, or overheat, doesn't matter what you do to em. They are
> either the most underated things, or the greatest things since
> sliced bread... take ur pick.
>
> Later... Jim VE7RF
>
Re: TL922 transformer and other

FRANCIS CARCIA
 

That is exactly why 400 Hz. is used in aircraft. but then some nut decided to do 270 VDC and kill people working on them. All to save the constant speed generator shaft interface.
A 50 Hz. transformer on 60 Hz will have lower magnetizing current but higher resistance. It might transfer less?peak power. I tried to make a transformer?with the same efficiency at 50 and 60 Hz once without changing taps?and could not do it. I came close though.

pentalab wrote:

--- In ham_amplifiers@yahoogroups.com, FRANCIS CARCIA
wrote:
>
> Lower frequency you need more primary turns so a higher tap to
reduce heating but this will reduce the output voltage due to turns
ratio change, gfz

### agreed. So, in essence... to properly run a xfmr on 50
hz.... you require MORE turns on the pri... and to keep the
turns ratio the SAME.... you will also have to add MORE turns on
the sec..... which the TL-922 may well allready have. The
UK/JA/ZL/VK have 50 hz power, so unless the NA version is 60 hz
only.... I'm guessing any oversea's 922 xfmr's will run just
fine on either freq.

### Too bad somebody way back when, didn't decide on something
higher.... like 70-80-90-100 hz power..... or even higher.. like
200 hz. These plate xfmr's, blower's, and eveything else could
have been made smaller.. and more eff.

### This is the problem with setting standards with 'new'
technology... they get outdated... fast.

Later.....Jim VE7RF


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