I enjoyed reading all through this one to see what all the little comments
were.

I think by all of us comparing notes and adding to each other's knowledge
base and laying it out here maybe only 13 Hams/CBers will blow their asses
off wiring amplifiers in their mobile homes this year.

I'm so glad we could be of assistance to the general population like this.
Somebody should give us a medal or something.

:-) BOB DD

Past days I was able to try a Jennings HiPot tester with some vacuum capacitors (all 250 pF, 30 KV; some were Jennings, China made, with ceramic bodies, others of another USA brand which I do not recall and the more "traditional" glass envelope). This tester feeds an AC voltage upto 60 KV peak; it has a control called "XC compensation". There was no manual so all was a try and guess. The effect I observed was to modify uAmmeter reading.
Which is the main purpose of that control?.

Best regards
Guillermo - LU8EYW.

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

--- In ham_amplifiers@..., "Robert B. Bonner"
<rbonner@> wrote:

Jim,

I know several years ago a friend sent me some copies of the

posts

on AMPS

when I wasn't a member. There were comments rather heated

regarding POWER

SERVICES and AC wiring to amps.

### yes.. that was cheap entertainment... happens every 4 yrs
on 'AMPS'.

I will end that quickly here as I won't tolerate incorrect info

to

pass me

by. You are a smart guy, very knowledgeable and have some good

experiences

but let's define power services / wiring correctly to avoid any

errors.

You and I are saying the same things but differently. Separated

by a common

language.

### agreed.

I worked three years as an electrician... Knew my business.

### I'm not.. but gotta work with em, and power engineers once
in a while... sometimes major projects.

Standard 220V residential circuits are two wire, the third wire

is

a GROUND

(Green) not a neutral.

### partially agreed . In Canada... ALL 220 v appliances

EXCEPT

a hot water tank, are 4 wire.

Most dryers are 2 wires plus ground here.

### Our dryers are all 4 wire. The motor is always 120 v..
separately internally fused from one of the hot legs. Dunno why..
seems silly a 220 v motor isn't used.



You wire your Ameritron its two

wires plus a ground.

### agreed... ditto with RL drake amps. No neutral needed. They
do it that way for one reason.... to sell em in EU/VK/ZL, etc...
where all they have is 220 V, 2 x hots + grnd. NO neutral in
the normal sense. In the UK... one side of the 220 V IS
grnded.... so look at that as one hot 220 v leg.. and one grnded
neutral leg.

If you have a 4 wire 220 circuit including Power Cord and a 4

conductor

plug... Two blacks a white and a green. You have 220 plus

neutral. This

will give you 220V via two 120 circuits and a ground. This is a

direct

extension of your panel service.

## agreed.

Most residential 220V items don't use 4 wire.

## see above.

Not to be confused with 3 Phase which is all different colors /

uses.

### agreed. With 3 phase.. u gotta worry about cw or ccw
rotation as well.... esp with interfacing with gen sets. 208 V
is popular... simply cuz any phase to neutral is 120 v. We

also

use 480 V 3 phase... but NO neutral.

In residential services in the states we tie the NEUTRALS and the

GROUND

Buss together in the main panels, however that NEVER by

definition

makes

them "the same thing". Neutral is Neutral and Ground is always

Ground.

### agreed.... but only main panels.... not sub panels. [strap
removed between gnd and neutral buss on all sub panels.]

Try switching them in a ground fault circuit and the breaker will

blow.

The green wire should NEVER conduct current. SO if you are

utilizing a 120

volt transformer somewhere in your homebrew for a control circuit

or

filament you should also be utilizing either a 220-120V step down
transformer in your construction OR a 4 wire 220 circuit to meet

code...

### yes... all of my 120 v blowers, fil xfmrs, etc... utilize the
4 wire cicuit. Each of the 120 v devices is individually

fused.

That meets code.

This is why large commercial HF power generators like the Henrys

(even the

8K) have 220-120 step down transformers inside them.

Others use 220V filament transformers not 120 to meet the

electrical code...

Why don't they use all 220 transformers? New regs requiring both

legs to

blow when one goes. They put gangbared main breakers on the

gear,

but

utilize 120 volt fuses for all the other small circuits to save

money. The

220-120 step down is cheaper to fuse than dual breakers on all

circuits.

Now will it work your way? That is 120V circuits wired to one

side of the

line? YES... Does it meet code? No...

### sure it does. You even said so a few paragraphs above...
as long as a 4 wire circuit is used... and individually sub
fused for the 120 v stuff.

### Any 220 v stuff HAS to use a tie bar between poles of
breaker. Having to open BOTH sides of a 220 v circuit just
killed any notion of using separate fuses per leg.... or
breakers without the ganged tie-bar. Dunno about my concept of
using BOTH a ganged 2 x pole breaker AND high speed fuses...

one

fuse per hot leg... downstream of ganged 2 x pole breaker. IF
just ONE fuse popped open.. the other fuse would remain intact...
and the slower 2 x pole ganged breaker would remain intact....
the result being.. only one leg is opened off. Meanwhile, ur

Dahl

plate xfmr loses power on primary..... until Joe ham... thinking
the power is OFF... gets in there...inside... grnds out one leg

of

xfmr.... and ends up with 120 V fed to the 240 v primary...
resulting in 1/2 normal plate V, etc. With one hot leg

still

intact [say it was 30-100A]... joe ham could still manage to
either electrocute himself... or melt stuff.

That being the case... and not being able to install fast fuses

per

leg..... to protect a HV supply.... the only real option is a

HV

fuse + glitch R. The best I can see for a 240 v primary... is
using "controlled magnetic hydraulic" breakers... with the 2 x
poles ganged together. Most of em come in different trip curve
ratings... so u want the FASTEST one possible.

I still can't find a half decent 100-A FAST magnetic

breaker....

in any catalog.... haven't looked at all of em though.

FYI The base Alpha 77 wasn't UL approved. It had a hot ground

wire. There

was a higher cost version that had a step down transformer in it

if you

REQUIRED a two wire circuit. That's mentioned right in their

manual.

### amazing. IF one is going to the trbl of installing a new
240 V line to schack.... you may as well do it right the 1st
time... and install a 4 wire curcuit.

You are correct on all the other points. The separate CB's

wouldn't fly

today without a tied together gangbar to kill both sides of the

AC

line.

A Grandfathered in system does not make it a good system. :-(

That's what I was referring to as CHEATING The System. Breaking

the

Electrical Code.

Since we are basically saying the same thing differently... We

have no

argument.

## agreed. I should obtain a copy of the latest code... since
mine is dated... I knew of SOME of the updates ... but not all....
like the new code sez all new homes must have arc detectors for
all bedrooms etc.

### In a lot of cases... if one is doing major updates on an
older home... they will want EXISTING... other stuff brought up
to new code standards.

### I dunno if AL conductor's are even allowed in homes
anymore. One home I had in the 80's had 12 ga AL wire...instead
of the usual 14 ga CU. I'm sure it was eventually banned. I
can see why. My son's bedroom duplex outlet ended up like

charcoal

one day. The AL conductor's... doesn't matter how tight u crank
the screws.... always ends up going slack.. then u get a
resistance joint, etc. Pwr co's use exclusively AL conductor's
in the field... cuz of weight... and cost.

They done away with aluminum romex cable, too many trailer and house
fires over it. The trailer (mobile home) industry used it the most.
Heavy aluminum cable has to be installed with an anti-corrosive on
the bare aluminum after it's stripped. The stuff we used came in a
plastic squirt bottle like ketchup is in at a restaurant. It was a
black greasy like stuff. You applied it to the bare aluminum wire
before it's placed in the terminal hole and the set screw tightened
down on it. It'll not pass an inspection if that's not applied to
aluminum wire anymore. They still use the large aluminum cable for
electric furnaces - heat pumps in homes.

later.... Jim VE7RF

BOB DD

Best,


Will

When I worked as an industrial electrician for several years after I
moved up here, we had them several places within the plant. However,
they were all on circuits that had several motors running. The push-
in jig at ACF Industries has about 16 hydraulic units on it, each
with about a 5 HP, 3 phase motor. That was where one large cap was
mounted overhead. I used to have to check it once a month on P.M. as
it had PCB's in the oil. We had to check it for leaks. There was a
few others, one in the power house where some M-G units were that
made the DC for some overhead cranes. That's about the only ones I've
been around besides some that were in plants where I was working in
engineering, and didn't have to fool with them anymore. I've never
seen any used with a transformers secondary. The reactance created by
motors can drop the power factor down a good bit. They were only
recommended to be used at a PF of under 0.80. Then, you spec them by
kVAr instead of capacitance. You find the recatance of the circuit in
question to calculate them, but they are sized and bought really by
specing a kVAr rating. What the kVAr rating is compared to
capacitance, I don't know. One might look into a catalog for them to
see. Then you also have to worry about harmonics too. They make these
up as PF corrector-harmonic filters also. They attach to each of the
three line legs of the 3 phase circuit. Some use a power monitor to
kick in and out the bank of caps when needed.

I think it would end up costing more, and placing more of a load on a
transformer by connection a cap across the secondary. It would be
similar to connecting a resistance of some amount in parallel with
the winding acting like a leak raising the current.

Best,

Will



--- In ham_amplifiers@..., "Robert B.
Bonner" <rbonner@...> wrote:

Guys,

My first job out of my undergrad program was with a building

automation

(energy) company. We installed PFC caps on buildings all over the

place.

At that time I wasn't the engineer doing this, but I was around it

enough.

There's formulas for balancing the act.. How much capacitance to

add etc

depending on the current PF and how many HP of motor load...

PFC is used because Electric motors exhibit a HELACIOUS Inductive

load on

the mains while converting to work.

In an inductive circuit the voltage leads the current by 90

degrees. This

inductive load tosses the power company out of SYNC. They are busy

trying

to match things up at the power plant.

They generate 3 phases of power. The load on the generators'

phases needs

to be balanced. A way off power factor screws the system. If

everybody

allowed the PF to get away from them you'd have a real mess... The

idea is

to make the current flow run in sync with the AC sign wave.

Commercial power is sold with a base rate for so many KWH, the

demand (how

fast you use it) and a premium penalty for power factor varying

from 100%.

I worked with an injection molding plastics factory. The big

injection

machines had very large motors and that place's PF was way the heck

out

there.

Instead of correcting the building.. We installed smaller

correction banks

on each machine (about 40 of them at that time) as you can have

too many

caps installed and shift the PF the other way.

We generally don't measure PF in residential as there isn't a huge

supply of

big motors throwing things off. Some areas with demand limiting of

energy

conservation do-do demand metering and control. None I've seen

here do PF

measuring at the residential level.

For the Super Big guns that are running 100 AMP primarys with three

phase

power supplies doing PFC will just make the power to the primary

smoother

and your power company happier. I don't think it is worth the

expense for

correction caps. Either way I would install them on the amplifier

not the

building.

BOB DD

-----Original Message-----
From: ham_amplifiers@...

[mailto:ham_amplifiers@...]

On Behalf Of craxd
Sent: Friday, November 17, 2006 6:22 PM
To: ham_amplifiers@...
Subject: [ham_amplifiers] Power factor correction for transformers

I looked through about every book I have on transformers and power
supplies, and never found anything about using a cap for power

factor

correction. There's plenty about using a cap with an AC motor, but
nothing about transformers. The Standard Handbook For Electrical
Engineers only show adding them to motor circuits or circuits

feeding

motor loads. Nothing under the transformer section.

The only power supplies to use a power factor correction cap was a
few switching power supplies. It was used after the rectifier and
before the choke though. It was never placed in the AC line. I did
see some series regulated supplies in transceivers that had a cap
across the secondary in a bridge rectifier supply, but it was for a
filter. Their values ran from 0.001 uF to 0.01 uF. Nothing of any
size.

The only way to cut back on magnetizing current is to use more iron
in the core lowering its flux density. The more iron for the same
amount of turns, the current drops. I researched magnetizing

current

in C-core Hipersil (or M-6) transformers some time back, and seen
they had a good bit more magnetizing current than most EI cores

using

M-19 steel. The reason being is they run Hipersil from 15 to 17
kilogauss. M-19 and M-22 are ran from 14 to 10 kilogauss. Over 15
kilogauss in Hipersil, the current really shoots up. The way to

cure

this is to have a transformer wound with the same number of turns,
but with a larger core area in either a C-core or an EI core. One
would have to tell the winder to use a lower flux density of say 12
to 10 kilogauss using a C-core with Hipersil or M-6 for a low
magnetizing current. M-19 for an EI core may be a better choice if
available as it will be a good bit cheaper. The core loss isn't

much

greater than M-6 either.

The links below go to several webpages and a couple of PDFs on the
subject.

switch_mode_power_supplies/

power_optimizing_singlestage_power/









Best,

Will





Yahoo! Groups Links

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

--- In ham_amplifiers@..., "Phil Clements" <philc@>
wrote:

I looked. In our breaker box, all the ground wires and all

the

Neutral wire connecct in one bus bar. How would it be

different

if

there were two bus bars that are connected by a bus-wire?

No electrical difference here; but if the breaker box is to be

used as

a sub-panel, you need seperate bus bars for the neutrals and

grounds

with a removable shorting strap between the two. Only in the main
service entrance panel do the neutrals and grounds all strap

together.

I guess a few bucks are saved by leaving out the strap and

insulation

for the two bus bars if one has no intention of ever changing a

main

panel over to a sub-panel.

### This is correct. Only SUB-panel's are wired for separate
grnd/neutral buss's.... via the shorting strap. I installed a 100
A sub panel... and such is the case. The reason is... they

want

any fault current to flow through the GRND buss bar... back to
main panel.... and NOT the neutral.

Correct, even though in reality, they tie together at the main panel.
The way it used to be, all the breaker boxes used for a service main
(main panel), like a 200 amp service in residential construction,
have a common bus bar for both the neutral and ground. This bus bar
is also bonded to the cabinet. These are the same as you will buy at
Lowes and Home Depot. When you want a sub panel, you ask for and buy
a sub panel as they're two different beasts. A sub panel could be
used as a main panel, but both bus bars (ground and neutral) have to
be tied together. Most sub panels though generally have a lower
current rating like 100 amps or less. I guess you could buy them
larger, but generally in residential construction, the sub panel is
smaller than the main panel. I don't know of any houses being built
today that use less than a 200 amp main. They used to have 100 amp
mains like this house had before I changed it out. I put in a heat
pump back in 1989 and had to upgrade to a 200 amp.

I'm talking about a hot to chassis short only... inside the HV
supply/amp/ anything else. This requires by the electrical
code... to have a separate GRND wire from sub panel to HV
supply/amp CHASSIS. Of course their is also a grnd wire tying
the main and sub panel together.

### any short from hot to neutral... in the HV
supply/amp/anything else including sub panel itself... and fault
current will flow back through the neutral.... back to main panel.

Correct. What Rich is saying is that since the ground and neutral tie
together at the main, they still in reality are the same wire. The
difference is that the neutral carries operating current back to the
main, and back to the C.T. of the transformer. Since the neutral
carries current, it's insulated. The ground though, being bare, is
used for safety and shouldn't have but a momentary fault current flow
in it. If a break in the hots insulation was to occur inside the
cable jacket, it should possibly (HOPEFULLY) short to the bare ground
and the fault current kick the breaker. That's why armored BX cable
is better than Romex. Since the bare ground is bonded to the steel
outlet or pull boxes, a short from the hot to a box will cause a
fault current to travel through the ground wire, back to the main,
and trip the breaker. The bare ground should be connected to the
chassis of the amp so that if a short happens between the chassis and
the hot (shorted transformer), the fault current will flow through
the ground wire, back to the main, and trip a breaker. The NEC
figures that the neutral is a current carrier and so it's insulated,
and the ground is only a temporary fault current carrier.

New TV sets throw this out the door as they all have a hot chassis
any more. The fault current goes back through the neutral if the fuse
don't blow.

Here, the C.T on a lot of transformers at the pole go to a ground rod
at the pole. The home also has a ground rod going to the ground/
neutral bus bar. Water pipes are not a good ground since most tap on
to the main water line via pvc pipe anymore, via a high pressure
fitting. Same goes for a well which uses PVC pipe. If the copper
water lines attached directly to a cast iron water main, it would be
pretty good. Most water mains here are thick wall, large ID plastic
anymore. You also would have a meter to feed through where a bond
jumper would need to be put across it. The water itself is not that
good of a conductor for a ground.

### This applies to any HV supply/linear amp as well. The
neutral if used.... is fed to it's own separate buss
bar/termination in the HV supply/amp...... and the neutral is
NEVER bonded to the chassis. If u did... u would have any and
all devices operating on 120 vac...having their return current
flowing back to sub panel via GRND.

See above. It's so you don't have operating current on a bare ground
wire.



And since the sub panel has

isolated grnd/neutral buss's..... this 120 vac current would
continue back to MAIN panel ..VIA the grnd wire tying the sub

and

main panel together.

### IE: The grnd wire[s] only are designed to carry FAULT
current.... and NEVER normal operating current.

Correct!

### When Rich or anybody else advocates bonding the Neutral to
the chassis in any HV amp/RF deck/anything else... BEWARE... you
are violating the electrical code in all 50 states, and all of
Canada.

### The shorting strap used in main panel is heavy ga copper
bar... and never wire. .... used to bond neutral buss and grnd
buss's together. [it might have to handle 100+ A] I have never
seen any panel yet, without isolated neutral and gnrd buss's.
That's cuz with isolated grnd/neutral buss's..... any panel can be
used as a main OR sub panel.

Here, you used to either buy a sub panel or a main panel. My Square D
main panel has a common bus bar where a series of holes are up either
side. There's two rows of set screws up the front over the holes. In
it, you can have a ground right under a neutral. I just seen a single
bus bar main panel by Square D at Lowes the other day while I was
looking around.

Your correct on a shorting jumper. It has to be able to handle the
maximum current the box is rated at. For a main, I prefer the single
bus bar.

The proper way of running a 115/230 Vac circuit is to use either 10-3
or 8-3 etc romex. There you have a black, red, white, and bare
ground. Black and Red are the two hots, White neutral, and bare is
ground.

A 230 Vac only circuit could be ran with say 10-2 or 8-2, but the
white would have to be re-colored by tape or heat shrink to pass an
inspection. In some areas, I'm not sure whether that would be
acceptable as local building codes can differ.

If using cordage like type SO cord, I always buy like 10-2 with black
and red instead of white. It costs a little more, but to me worth it.
Ground is always green in all.

Some cordage like is being used in computer power cables though have
blue and brown or black for the power if I recall, and green as
ground.

Grey 3-wire zip type cord can be used as it has no color except the
green ground in the middle. This is similar to dryer pig tails, etc.
I've used this cable to wire 60 amp fused disconnects for 225 amp
welders (buzz boxes).

The big heavy 230 vac cable for a heat pumps, etc main current is
similar to service entry cable in a grey rubber jacket. The two hots
are black with a bare ground. The wire is aluminum. I'm not for sure
the current capacity of the stuff I have here though.

Later... Jim VE7RF

(((73)))
Phil Clements, K5PC

Best,

Will

--- In ham_amplifiers@..., "Robert B. Bonner"
<rbonner@...> wrote:

Jim,

I know several years ago a friend sent me some copies of the posts

on AMPS

when I wasn't a member. There were comments rather heated

regarding POWER

SERVICES and AC wiring to amps.

### yes.. that was cheap entertainment... happens every 4 yrs
on 'AMPS'.

I will end that quickly here as I won't tolerate incorrect info to

pass me

by. You are a smart guy, very knowledgeable and have some good

experiences

but let's define power services / wiring correctly to avoid any

errors.

You and I are saying the same things but differently. Separated

by a common

language.

### agreed.

I worked three years as an electrician... Knew my business.

### I'm not.. but gotta work with em, and power engineers once
in a while... sometimes major projects.

Standard 220V residential circuits are two wire, the third wire is

a GROUND

(Green) not a neutral.

### partially agreed . In Canada... ALL 220 v appliances EXCEPT
a hot water tank, are 4 wire.

Most dryers are 2 wires plus ground here.

### Our dryers are all 4 wire. The motor is always 120 v..
separately internally fused from one of the hot legs. Dunno why..
seems silly a 220 v motor isn't used.



You wire your Ameritron its two

wires plus a ground.

### agreed... ditto with RL drake amps. No neutral needed. They
do it that way for one reason.... to sell em in EU/VK/ZL, etc...
where all they have is 220 V, 2 x hots + grnd. NO neutral in
the normal sense. In the UK... one side of the 220 V IS
grnded.... so look at that as one hot 220 v leg.. and one grnded
neutral leg.

If you have a 4 wire 220 circuit including Power Cord and a 4

conductor

plug... Two blacks a white and a green. You have 220 plus

neutral. This

will give you 220V via two 120 circuits and a ground. This is a

direct

extension of your panel service.

## agreed.

Most residential 220V items don't use 4 wire.

## see above.

Not to be confused with 3 Phase which is all different colors /

uses.

### agreed. With 3 phase.. u gotta worry about cw or ccw
rotation as well.... esp with interfacing with gen sets. 208 V
is popular... simply cuz any phase to neutral is 120 v. We also
use 480 V 3 phase... but NO neutral.

In residential services in the states we tie the NEUTRALS and the

GROUND

Buss together in the main panels, however that NEVER by definition

makes

them "the same thing". Neutral is Neutral and Ground is always

Ground.

### agreed.... but only main panels.... not sub panels. [strap
removed between gnd and neutral buss on all sub panels.]

Try switching them in a ground fault circuit and the breaker will

blow.

The green wire should NEVER conduct current. SO if you are

utilizing a 120

volt transformer somewhere in your homebrew for a control circuit

or

filament you should also be utilizing either a 220-120V step down
transformer in your construction OR a 4 wire 220 circuit to meet

code...

### yes... all of my 120 v blowers, fil xfmrs, etc... utilize the
4 wire cicuit. Each of the 120 v devices is individually fused.
That meets code.

This is why large commercial HF power generators like the Henrys

(even the

8K) have 220-120 step down transformers inside them.

Others use 220V filament transformers not 120 to meet the

electrical code...

Why don't they use all 220 transformers? New regs requiring both

legs to

blow when one goes. They put gangbared main breakers on the gear,

but

utilize 120 volt fuses for all the other small circuits to save

money. The

220-120 step down is cheaper to fuse than dual breakers on all

circuits.

Now will it work your way? That is 120V circuits wired to one

side of the

line? YES... Does it meet code? No...

### sure it does. You even said so a few paragraphs above...
as long as a 4 wire circuit is used... and individually sub
fused for the 120 v stuff.

### Any 220 v stuff HAS to use a tie bar between poles of
breaker. Having to open BOTH sides of a 220 v circuit just
killed any notion of using separate fuses per leg.... or
breakers without the ganged tie-bar. Dunno about my concept of
using BOTH a ganged 2 x pole breaker AND high speed fuses... one
fuse per hot leg... downstream of ganged 2 x pole breaker. IF
just ONE fuse popped open.. the other fuse would remain intact...
and the slower 2 x pole ganged breaker would remain intact....
the result being.. only one leg is opened off. Meanwhile, ur Dahl
plate xfmr loses power on primary..... until Joe ham... thinking
the power is OFF... gets in there...inside... grnds out one leg of
xfmr.... and ends up with 120 V fed to the 240 v primary...
resulting in 1/2 normal plate V, etc. With one hot leg still
intact [say it was 30-100A]... joe ham could still manage to
either electrocute himself... or melt stuff.

That being the case... and not being able to install fast fuses per
leg..... to protect a HV supply.... the only real option is a HV
fuse + glitch R. The best I can see for a 240 v primary... is
using "controlled magnetic hydraulic" breakers... with the 2 x
poles ganged together. Most of em come in different trip curve
ratings... so u want the FASTEST one possible.

I still can't find a half decent 100-A FAST magnetic breaker....
in any catalog.... haven't looked at all of em though.

FYI The base Alpha 77 wasn't UL approved. It had a hot ground

wire. There

was a higher cost version that had a step down transformer in it

if you

REQUIRED a two wire circuit. That's mentioned right in their

manual.

### amazing. IF one is going to the trbl of installing a new
240 V line to schack.... you may as well do it right the 1st
time... and install a 4 wire curcuit.

You are correct on all the other points. The separate CB's

wouldn't fly

today without a tied together gangbar to kill both sides of the AC

line.

A Grandfathered in system does not make it a good system. :-(

That's what I was referring to as CHEATING The System. Breaking

the

Electrical Code.

Since we are basically saying the same thing differently... We

have no

argument.

## agreed. I should obtain a copy of the latest code... since
mine is dated... I knew of SOME of the updates ... but not all....
like the new code sez all new homes must have arc detectors for
all bedrooms etc.

### In a lot of cases... if one is doing major updates on an
older home... they will want EXISTING... other stuff brought up
to new code standards.

### I dunno if AL conductor's are even allowed in homes
anymore. One home I had in the 80's had 12 ga AL wire...instead
of the usual 14 ga CU. I'm sure it was eventually banned. I
can see why. My son's bedroom duplex outlet ended up like charcoal
one day. The AL conductor's... doesn't matter how tight u crank
the screws.... always ends up going slack.. then u get a
resistance joint, etc. Pwr co's use exclusively AL conductor's
in the field... cuz of weight... and cost.

later.... Jim VE7RF

BOB DD

Guys,

My first job out of my undergrad program was with a building automation
(energy) company. We installed PFC caps on buildings all over the place.
At that time I wasn't the engineer doing this, but I was around it enough.
There's formulas for balancing the act.. How much capacitance to add etc
depending on the current PF and how many HP of motor load...

PFC is used because Electric motors exhibit a HELACIOUS Inductive load on
the mains while converting to work.

In an inductive circuit the voltage leads the current by 90 degrees. This
inductive load tosses the power company out of SYNC. They are busy trying
to match things up at the power plant.

They generate 3 phases of power. The load on the generators' phases needs
to be balanced. A way off power factor screws the system. If everybody
allowed the PF to get away from them you'd have a real mess... The idea is
to make the current flow run in sync with the AC sign wave.

Commercial power is sold with a base rate for so many KWH, the demand (how
fast you use it) and a premium penalty for power factor varying from 100%.

I worked with an injection molding plastics factory. The big injection
machines had very large motors and that place's PF was way the heck out
there.

Instead of correcting the building.. We installed smaller correction banks
on each machine (about 40 of them at that time) as you can have too many
caps installed and shift the PF the other way.

We generally don't measure PF in residential as there isn't a huge supply of
big motors throwing things off. Some areas with demand limiting of energy
conservation do-do demand metering and control. None I've seen here do PF
measuring at the residential level.

For the Super Big guns that are running 100 AMP primarys with three phase
power supplies doing PFC will just make the power to the primary smoother
and your power company happier. I don't think it is worth the expense for
correction caps. Either way I would install them on the amplifier not the
building.

BOB DD

I looked through about every book I have on transformers and power
supplies, and never found anything about using a cap for power factor
correction. There's plenty about using a cap with an AC motor, but
nothing about transformers. The Standard Handbook For Electrical
Engineers only show adding them to motor circuits or circuits feeding
motor loads. Nothing under the transformer section.

The only power supplies to use a power factor correction cap was a
few switching power supplies. It was used after the rectifier and
before the choke though. It was never placed in the AC line. I did
see some series regulated supplies in transceivers that had a cap
across the secondary in a bridge rectifier supply, but it was for a
filter. Their values ran from 0.001 uF to 0.01 uF. Nothing of any
size.

The only way to cut back on magnetizing current is to use more iron
in the core lowering its flux density. The more iron for the same
amount of turns, the current drops. I researched magnetizing current
in C-core Hipersil (or M-6) transformers some time back, and seen
they had a good bit more magnetizing current than most EI cores using
M-19 steel. The reason being is they run Hipersil from 15 to 17
kilogauss. M-19 and M-22 are ran from 14 to 10 kilogauss. Over 15
kilogauss in Hipersil, the current really shoots up. The way to cure
this is to have a transformer wound with the same number of turns,
but with a larger core area in either a C-core or an EI core. One
would have to tell the winder to use a lower flux density of say 12
to 10 kilogauss using a C-core with Hipersil or M-6 for a low
magnetizing current. M-19 for an EI core may be a better choice if
available as it will be a good bit cheaper. The core loss isn't much
greater than M-6 either.

The links below go to several webpages and a couple of PDFs on the
subject.








power_optimizing_singlestage_power/









Best,

Will

--- In ham_amplifiers@..., "Phil Clements" <philc@...>
wrote:

I looked. In our breaker box, all the ground wires and all the
Neutral wire connecct in one bus bar. How would it be different

if

there were two bus bars that are connected by a bus-wire?

No electrical difference here; but if the breaker box is to be

used as

a sub-panel, you need seperate bus bars for the neutrals and

grounds

with a removable shorting strap between the two. Only in the main
service entrance panel do the neutrals and grounds all strap

together.

I guess a few bucks are saved by leaving out the strap and

insulation

for the two bus bars if one has no intention of ever changing a

main

panel over to a sub-panel.

### This is correct. Only SUB-panel's are wired for separate
grnd/neutral buss's.... via the shorting strap. I installed a 100
A sub panel... and such is the case. The reason is... they want
any fault current to flow through the GRND buss bar... back to
main panel.... and NOT the neutral.

I'm talking about a hot to chassis short only... inside the HV
supply/amp/ anything else. This requires by the electrical
code... to have a separate GRND wire from sub panel to HV
supply/amp CHASSIS. Of course their is also a grnd wire tying
the main and sub panel together.

### any short from hot to neutral... in the HV
supply/amp/anything else including sub panel itself... and fault
current will flow back through the neutral.... back to main panel.

### This applies to any HV supply/linear amp as well. The
neutral if used.... is fed to it's own separate buss
bar/termination in the HV supply/amp...... and the neutral is
NEVER bonded to the chassis. If u did... u would have any and
all devices operating on 120 vac...having their return current
flowing back to sub panel via GRND. And since the sub panel has
isolated grnd/neutral buss's..... this 120 vac current would
continue back to MAIN panel ..VIA the grnd wire tying the sub and
main panel together.

### IE: The grnd wire[s] only are designed to carry FAULT
current.... and NEVER normal operating current.

### When Rich or anybody else advocates bonding the Neutral to
the chassis in any HV amp/RF deck/anything else... BEWARE... you
are violating the electrical code in all 50 states, and all of
Canada.

### The shorting strap used in main panel is heavy ga copper
bar... and never wire. .... used to bond neutral buss and grnd
buss's together. [it might have to handle 100+ A] I have never
seen any panel yet, without isolated neutral and gnrd buss's.
That's cuz with isolated grnd/neutral buss's..... any panel can be
used as a main OR sub panel.

Later... Jim VE7RF

(((73)))
Phil Clements, K5PC

Hi-
I have some NOS TV transmiting tubes FS, FU-720F( Same as 7F71RA),tetrode, Palate dissipation: 3500W filament:4V/78A
I ask $500/ea. I can pay the shipping cost(surface mail). JPG and detail specs on request.
73! Hsu

On Nov 17, 2006, at 9:18 AM, Robert B. Bonner wrote:

-----Original Message-----
From: ham_amplifiers@...
[mailto:ham_amplifiers@...]
On Behalf Of R L Measures
Sent: Friday, November 17, 2006 5:55 AM
To: ham_amplifiers@...
Subject: Re: [ham_amplifiers] NOS cermic-metal tube burn in
...

There was a time that Eimac had issues with quality on the 8877,

a weld came

loose INSIDE the tube separating the cathode from the pins.

Did you autopsy the tube, or did you base this diagnosis on ohmmeter
measurements?

*** In the case of the 8877 back in 1980 it was pretty obvious the
amp was
working one day and then when fired up the next one of the tubes
wasn't
home. I did the pull one out at a time to figure out which one
didn’t come
online and then placed the calls.

I checked filaments and both tubes were OK. All the cathode pins
were still
connected together. But apparently something else had stopped working.

Sounds like the heat dam problem. Appsaently the problem lasted c.
13-months.

... They tore the tube apart and in fact it was the warrantable

quality failure problem and they sent me a new tube.

What failed?

*** A weld in the actual cathode, I never saw the tube again. But
the pins
stay connected and the cathode separates from the pins.

I figure this 3CPX1500 has the same type of failure, though not a
warrantee
able situation in this failed in an MRI machine tube.

I have not heard of the 3cpx1500A7 having a heat damn problem. What
is the date code?

...

*** Yeah, there you go. But still no self respecting Collins
engineer would
ever stick 6 in a box and call it a day.

A knowledgeable engineer knows that paralleling tubes makes 10m
operation no more difficult than doing it with one tube.

cheers, Bob

R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

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

... and the audio quality is superb.

**** Yes for an early SSB rig they were great.

They were better than later Collins transmitters because they used

a 2.7KHz mechanical filter -- i. e., one that was wide enough to
pass a humanoid male voice with minimal loss of lows. Later
Collins transmitters used a 2.4KHz filter, which is wide enough
for female voices but NOT male voices.

### Huh ? Most women sound like crap on a ssb Tx.. simply cuz
the upper freq response doesn't go high enough. Later Collins
S-line KWM2/A rigs all used a single 2.1 khz mech filter..
with lousy skirts.

### I installed a 5.7 khz 10 pole Collins mech filter in all
my Yaesu FT-1000-D's and also my Yaesu MK-V's. Also beware,
Collins spec's their mech filter's at the -3db points... NOT
the -6db points !! My 5.7 khz filter is actually a little
wider at the -6db points. This filter of course is used at
the 455 khz IF. The 8215 khz xtal filter was replaced with a
Inrad 6 khz [-6db] 8 pole, steep skirted unit. Each filter
has a 1.5 : 1 shape factor..... and cascaded.. the PAIR have an
excellent 1.3 : 1 shape factor !

### with that combo... then you can have really good sounding
ssb... as good or better than our local 10 kw AM broadcast station.

### We also found that by replacing the analog BM pot with a 10-20
turns pot, OR paralleling a resistor with existing pot... that an
easy -75 db of CXR rejection is obtained.... and that's with the
cxr osc tweaked for just 30 hz @ -6db . With cxr osc set to
300 hz.. @ -6db.... cxr suppresion is >100 db... superb.



other than those like that of Verne

Troyer, a.k.a. "Mini Me" of Austin Powers movie fame.

I'm more of a KW-1 fan only
because they were total brutes. I'm sure you agree.

I am not a fan of AM because it's a watt-waster and most of the

Hams who run AM are lock-to-talk time-wasters.

#### I use VOX AM... works superb. Also, you can install a wider
AM filter in the yaesu MK-V's... for deluxe AM. You can see all
of this info on the 85 page document W5CUL and myself wrote...
posted on also on ..
under MK-V mods.

I think the Collins
engineers sort of let us down a little by not putting bigger

tubes

in them
from the start.

Agreed, Bob, but in those days the choices were few between the
7580/4cx250R and the 8170.

They of course wanted a transmitter to match the 75A-4 but
still. The 4X150 was a sexy little tube.

Six of them in parallel would have been about right for the then
legal 1000w DC indicated input on SSB.

#### Six 8170's would make some racket too.

later.... Jim VE7RF

...
R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Nov 17, 2006, at 6:57 AM, n6jp wrote:

This is somewhat less than wonderful. OTOH, with an 8171 at sea-
level using 0.4-inches of WC will dissipate c. 4500w. This allows
using a 9000v anode supply - but only for
SSB. Thus, on SSB with a 1500v screen supply, the headroom is 7500v.

Rich, using a 8171, what specs would you recommend for a mode such as
rtty?

Jer: With the aforementioned cooling air-pressure, RTTY would require that the anode PS potential be reduced to c. half of that for SSB. This is semi-easy if the HV-PS is FWD/FWB switchable.

end

Jer
...

R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

This is somewhat less than wonderful. OTOH, with an 8171 at sea-
level using 0.4-inches of WC will dissipate c. 4500w. This allows
using a 9000v anode supply - but only for
SSB. Thus, on SSB with a 1500v screen supply, the headroom is 7500v.

Rich, using a 8171, what specs would you recommend for a mode such as
rtty?

Jer

R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Nov 17, 2006, at 3:04 AM, badgerscreek wrote:

Anyone built a desktop amplifier with a very large tube, say a
3cx3000, YC156 or even a 8170?

Yes, I built an 8170 amplifier, however, the 8171 is the same tube inside but it has a more efficient anode cooler which works ok with a 1700rpm blower instead of a 3400rpm one.

I am thinking about tackling such a project, not for huge power
output but more from the point of view of running a very low speed
blower that is silent. I would prefer to use a instant on tube. I dont
mind a seperate external power supply. Filament heat is not a big
issue with me either. A 8170 for example can been cooled with a blower
with less than .4 inches of back pressure at low to medium power. Any
thoughts?

Greg -- An 8170 at sea-level with 0.4 inches of water-column is good for 2000w dissipation. Since the required ZSAC for good linearity is 0.5A, 2000w would limit the anode supply to c. 4000v. Since the usual screen potential for an 8170 (or 8171) is 1300 to 1500 volts. a 4000v anode supply would allow only about 2500v of anode headroom. This is somewhat less than wonderful. OTOH, with an 8171 at sea- level using 0.4-inches of WC will dissipate c. 4500w. This allows using a 9000v anode supply - but only for
SSB. Thus, on SSB with a 1500v screen supply, the headroom is 7500v. The bottom line is that with 0.4" of cooling, the 8171's output is c. 3x greater than 8170's output. At 9kV and 1500Sc-V, an 8171 should do c. 19k-pep out on SSB.

If you have a good-emission 8170 and you would like for it to have an 8171 anode cooler, the anode cooler can easily be swapped out by a tube rebuilder.
end

Greg

R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Nov 16, 2006, at 1:30 PM, Robert B. Bonner wrote:

Below,

-----Original Message-----
From: ham_amplifiers@... [mailto:ham_amplifiers@...]
On Behalf Of R L Measures
Sent: Thursday, November 16, 2006 2:48 PM
To: ham_amplifiers@...
Subject: Re: [ham_amplifiers] NOS cermic-metal tube burn in

On Nov 16, 2006, at 11:06 AM, Robert B. Bonner wrote:

RL,

Because he adjusted the BIAS to make the 400-500 ma of resting plate
current.

You have to very closely read his message. There's a very slight
language
barrier.

I wondered about that problem after I clicked Send. However, if the
tubes will draw 500mA, there can not be a lack of emission provided
they do that briefly at 0 grid volts.

**** Yes exactly, the emission seems good by rocking the bias. Have to be
careful here as 400ma is 800 watts dissipation. But if it was just a quick
check...

I'm hoping he's not going all the way to zero control grid volts,

To check emission capability for Class AB1 operation, one must (very briefly) measure the anode-I at 0 grid volts.

I'm sure
he's just moving it a bit.

That's why I figured the issue is alignment and driver power. Or possibly
some other issue not finals related. We'll have to wait for his response to
the questions.

That's why I'm wondering a couple things. Curious what tubes were
in the
transmitter previously... and if the unit makes full power with a
different
set of tubes.

I'm thinking these 4CX250's are quite possibly just being
difficult. It
doesn't take much to detune the driver tuning and lose drive. I'm

not

familiar with the durability of Chinese 4CX250's in storage, but
the Eimac
ones are like concrete. Seems you can pull an Eimac one out of the
soup and
crank it up any day of the week.

I've seen a number of Eimac pulls that were kaput.

****I was referring to new old stock 4CX250's the 20 year old ones or more,
they just seem to keep right on ticking no matter where you get them from if
new. Pulls are always a crap shoot.

I just had a beautiful 1 YO 3CPX1500A7 test bad last night. Obviously a
hammered cathode as it drew no plate current, made no grid current or RF.
But the filament warmed up nicely. This one was a new tube placed in an MRI
and it faulted... Obviously the fault was a violent one. Really too bad, I
was getting emotionally attached to that tube, now I need to send it back to
the guy. I had thought I had a great purchase there.

Do you have access to a high-potential tester?

I had a new low hours 8877 back in 1980 do the same thing without a fault.
There was a time that Eimac had issues with quality on the 8877, a weld came
loose INSIDE the tube separating the cathode from the pins.

Did you autopsy the tube, or did you base this diagnosis on ohmmeter measurements?

Just after turning it on when keyed my 77SX went to half resting current.
This was my amplifier and I just about lost it. I worked for a medium sized
Eimac dealer at the time. I talked directly first to Eimac, then ETO and
since that tube was within warranty I went through all the standard return
paperwork. They tore the tube apart and in fact it was the warrantable
quality failure problem and they sent me a new tube.

What failed?

The KWS-1 is a persnickety device in the first place, but once
lined up they
work well.

... and the audio quality is superb.

**** Yes for an early SSB rig they were great.

They were better than later Collins transmitters because they used a 2.7KHz mechanical filter -- i. e., one that was wide enough to pass a humanoid male voice with minimal loss of lows. Later Collins transmitters used a 2.4KHz filter, which is wide enough for female voices but not male voices other than those like that of Verne Troyer, a.k.a. "Mini Me" of Austin Powers movie fame.

I'm more of a KW-1 fan only
because they were total brutes. I'm sure you agree.

I am not a fan of AM because it's a watt-waster and most of the Hams who run AM are lock-to-talk time-wasters.

I think the Collins
engineers sort of let us down a little by not putting bigger tubes in them
from the start.

Agreed, Bob, but in those days the choices were few between the 7580/4cx250R and the 8170.

They of course wanted a transmitter to match the 75A-4 but
still. The 4X150 was a sexy little tube.

Six of them in parallel would have been about right for the then legal 1000w DC indicated input on SSB.
...
R L Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

开云体育

Below,

Greetings all:

I am looking for a Heath Warrior that has been mostly trashed out. Mainly I need chassis parts. Funds are limited.

73,
Mike, W5UC