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

On Oct 7, 2006, at 3:44 AM, badgerscreek wrote:

Palstar has a new tuner on their web page for those who are
interested.

Its rated at 10kw pep. To me it seems marginal to be rated at

10KW pep with 6kv vacuum variables. Even 6kv at 1500 watt legal
limit is barely capable of handling many common antennas like
doublets and loops.

RICH SEZ.. with a 1000-ohm antenna, 5kV-pk is 12,500w-rms.

The roller inductor is listed as having #10 wire. I would have
thought that a 1/2 inch flat strip roller inductor would have

been more appropiate.

### That 10 ga wire roller inductor with the single pickup
wheel is THE weak link in the tuner. They rate this tuner at
5 kw cxr CCS. I find it amusing that they market it at....
"SW AM broadcast"!! 2 kw of cxr = 10 kw pep on AM with
125% modulation. IF those PAIR of JENNINGS 1000 pf caps are
new [ 10 kv test, 6 kv working].... this will be one of the most
expensive tuners's ever made.... several thousand dollars
easily just for those 2 x caps.... unless they are using surplus
caps....... then they lose it with that undersized 10 ga roller.

### 3/8" or 1/2" ribbon.... edge wound... and a tapered pitch
at the high freq end would be the real deal. As is... notice
how there is a 4" square 100 cfm blower at the back of the cab...
pointed at the puny roller coil !! Nuts.




### That SPST 25 kv vac relay depicted in the new Palstar
10 kw tuner is the same one I use to shunt out the larger of the
plate chokes... in my two piece plate choke set up. BRAND NEW
SPST NC 12 vdc kilovac relays are currently available from
Allen Bond.... beautiful units..... and not RF rated !! I picked
up 3 of em a month ago. Their purpose is to stand off HV.

RICH SEZ.. Depends on operating Q, Greg.

### Agreed. This new Palstar IS a T tuner... with the coil
hooked to to the junction point of the two series caps... and
other end of roller coil goes to chassis. On a T tuner...
lowest Q is obtained with HIGH C.... LOW L [it's the opposite of
a PI-NET] Lowest Q will result in lowest RF circulating
currents through the vac caps [no big deal since they are both
rated > 100 A] and also lowest RF current through the marginal
roller coil.


If the Palstar tuner is an L-network,

RICH SEZ... #10 Cu should be okay for 10k of SSB -- unless the
antenna Z is extraordinarily high -- such as with a Hertz
antenna. (half-wave end- fed against ground).

### 10 kw on ssb = 2kw AVERAGE = 6.3 A Hit it with a dead
cxr... just once... for a few seconds... and poof.. bye bye
roller coil [what will vaporize will be the roller contact
itself] 10 kw cxr = 14.2 A !!! Try 14 A of RF on 10m..
and you will be in for a rude awakening. You need 1/4" tubing
for 10 kw CXR on 10m.



### It's NOT an L network. The unit depicted is a
conventional T. [which won't give u any additional harmonic
suppression]. BTW...Palstar does make a balanced
L..... using the same type of small ga wire roller inductor's
[2 x used synced together... and ONE cap] The discontinued
balanced L they USED to make was the real deal... used a pair of
edge wound roller inductor's.

However it may just be a line flattener and my judgement might

be flawed!

## IF it's just a line flattener you want... an L network with
one vac cap and one edge wound roller [or tubing roller]
would work just fine.

## This Palstar tuner is gonna be for the "elite class" [read
deep pockets] and it's just another device that's very simple to
build .....correctly.

### IF u want a tuner for a balanced line... use a balanced L....
with TWO edge wound rollers.[synced together with the usual
rubber belt.. with teeth in the belt and matching teeth on the
pulleys] .... and ONE vac cap. [think of 2 x L networks in a
balanced config... the 2 x caps would be in SERIES.... so a PAIR
of say 1000 pf vac caps could easily be replaced with just ONE
500 pf vac cap ! Rich has it on his site... he also had it right
two decades b4 anybody else.

### A 10 kw tuner used in a 50 ohm coax application is
plane nuts. Ham's haven't yet figured out that coax tuners
should be loacted at the OTHER end of the coax... right at the
ant. With 10 kw and a tuner that will handle it.... you still
have high swr on the coax/connectors/ remote switch boxes/ants,
remote LC boxes used to stack yagi's, "stackmaster's ", etc.

### 10 kw into say a 2:1 load consisting of say a 25 ohm Z
is bad news. The RF currents will skyrocket. 10 kw into a 25
ohm load = 20 A !!

### Most 20-10m yagis' these days are very broadbanded.. esp
the OWA/F-12 designs... whereby the 1st director is very close to
the DE... resulting in a direct 50 ohm Z... no hairpin/beta
match/gamma//omega/ needed.

### On 40m yagi's...[and also 80m rotary dipoles] simply add
some series inductance in each leg... [small coils]. These
coils are simply shorted out with a DPST P+B 30 A relay... or a
DPST vac relay can be used. On my F-12 EF-180B 80M rotary
dipole... it only has a 68' long DE... and 2:1 BW is only 62
khz. To make it cover the entire band... a waterproof fiberglass
[non metallic] box is used.. at the feedpoint. This box
contains 3 x DPST relays... and 6 x small coils. The coils
are terminated directly to the relay screw terminals.

### with 3 x relays and 6 x small coils [3 on each side of the
relays] 8 x SEGMENTS, each 62 khz wide, can be obtained ! IE:
flat swr.... and toss the coax tuner away. On 40m.... only 1 x
relay is required... and 2 x small coils.

### All that is being done here, is you are adding a tiny bit of
XL right at the feedpoint. With ALL the relay's operated... [and
all coils shorted out] the DE is adjusted to resonsate at the
HIGH end of the band. By switching the various relay combo's...
[and UN shunting the coils].. progresively more and more XL is
being added to the feedpoint of the ant... and lowering it's
resonate freq. SWR? What swr ? It's gone.

### F-12 uses 12 ga THNN wire [ home depot stuff] for it's
coils on both it's 80 + 40m boxes. I was gonna replace em with
10 ga THNN wire..[more home depot stuff] .... then decided to just
use 8 ga polyimide MAGNET wire [15 kv insulation] Now 8 ga
wire is only .128" and a bit more with the polyimide glop
on.... and is about the same overall OD as using 12 ga THNN
with it's plastic insulation [good for only a few hundred V]

### Of course a control cable is needed to run the relays...
and with all relays de-energized.. the default will of course be
all coils in the circuit = resonate in the lowest part of the
band.

### I'll post some pix down the road of the inside's of this
small box. This technique can easily be used on ANY coax fed
dipole/inverted vee /yagi.

### BTW.... IF you want to run more than 5 kw.... DON'T use
a SO-239 /PL-259 combo [they are rated for 500 V rms = 5 kw
into 50 ohms + flat swr]....and ditto with the Type N [handles
LESS pwr thasn a teflon/silver UHF connector's] Instead use a
modern 7-16 DIN connector. There are plenty of em around
surplus. For new ones... I get em from the TRU connector
co... in Peabody Mass. TRU makes loads of chassis 7-16 DINS... I
use the one with the LONGEST pin sticking out the back end....
makes it easier to terminate copper strap on.

### A 7-16 Din uses a huge 7mm center female... .284" !! and
is rated for around 2700 V rms [3800 v peak] The chassis
connector is a bit bigger than a SO-239.... 1.25" square vs
1" square. Andrews doesn't make UHF connector's for 7/8"
heliax anymore... only 7-16 DINS and Type N. A Type N has a
center pin in it virtually identical to a BNC. IMO Type N is
more failure prone junk.

## I don't see any 7-16 DIN on this Palstar 10 kw tuner.

Later....... Jim VE7RF

开云体育

John,

There's two things I always do. Admit when I'm wrong, and correct what
I said wrong. My memory I've found, now that I'm getting older, don't
work as quick as it did. Of course, I've not studied nor worked on
automobile engines since I was in my teens. It's funny, one actually
remembers things, but it takes something or someone else to jar their
memory to get them to.

Best,

Will

Tony,

Sorry about that, I thought you said 4 cylinder. However, you did jar
my memory again about the distributor speed. The 4 cylinders
distributor has to turn at 1/2 speed compared to the crank to allow 2
cylinders to fire per crank revolution. The other 2 are in their
exhaust stroke. The 6 and 8 cylinder does the same thing. A 6
cylinder, 3 per crank rev, and 8 cylinder, 4 per crank rev. This adds
a divide by two when finding the frequency.

Best,

Will

--- In ham_amplifiers@..., Tony King - W4ZT <w4zt-060920@.
..> wrote:

Will,

craxd wrote:

Tony,

<snip>

"at 2000 RPM that would be 1000 sparks per minute or 16.666..."

No, for a 4 cylinder at 2000 RPM you would have 4000 sparks
(pulses) per minute since 2 of the 4 cam lobes close the points
twice per crank revolution. Since the crank is turning at 2000
RPM, the points close twice per crank revolution instead of 4
times. 4000 / 60 = 66.67 Hz.

You misquoted me out of context, Will...

I said:

"A single cylinder 4 cycle engine will fire only once per every 2
rotations. at 2000 RPM that would be 1000 sparks per minute or 16.

666...

sparks per second."

I said SINGLE cylinder and you compared it directly to 4 cylinder.
<snip>

73, Tony W4ZT

Hi Dick,

How hot is the step-down toroid on the output getting?
The problem with air caps will be the rotor contacts which have to carry
about 25A and probably more on 10m in the DX4.
It looks they are using quite normal contacts on the caps.
Even the very high power caps of Oren Elliot are only good for 30A.
I use vacuum variables for this reason and their size also in my low
impedance amps like 3xRS1072C

73
Peter

________________________________

From: ham_amplifiers@... [mailto:ham_amplifiers@...]
On Behalf Of Dick

See the pics in the photo section.
The taps are done with bare wire, but the coil is done with double
wire in a teflon sleeve.
In SSB service this works good, but in my opinion the toroid wound
coil section gets a bit too hot in higher duty modes.

### On Emtron's website... as of 2 mins ago... the DX-4 is NOT
listed anywhere !! Nor is it listed under "orders" or anywhere
else. However... do a google on dx-4... and loads of stuff
appears. I know it's an export only. Is it still being
made ????

The DX4 is currently made in larger numbers than all other Emtron HF
amps according to Rudi Breznik.
Because of the relatively low B+ voltage the tank caps are air caps
for both tune and load which reduces the costs for the tank circuit.

See the pics in the photo section.
The taps are done with bare wire, but the coil is done with double
wire in a teflon sleeve.
In SSB service this works good, but in my opinion the toroid wound
coil section gets a bit too hot in higher duty modes.

### On Emtron's website... as of 2 mins ago... the DX-4 is NOT
listed anywhere !! Nor is it listed under "orders" or anywhere
else. However... do a google on dx-4... and loads of stuff
appears. I know it's an export only. Is it still being
made ????

The DX4 is currently made in larger numbers than all other Emtron HF
amps according to Rudi Breznik.
Because of the relatively low B+ voltage the tank caps are air caps
for both tune and load which reduces the costs for the tank circuit.

More info including pics of the 3 phase power supply on the Emtron
owners yahoo group,



There are rumours about the design of a GU84B three holer but I have
no confirmation for this.

Cheers, Dick
PA3DUV


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

--- In ham_amplifiers@..., PA3DUV <pa3duv@> wrote:

Peter,

The 200 C was the coil wire, not the toroid itself.
The toroid barely heated up.

#### 200 deg C = 400 deg F !! Which imo is way too hot.

### Looks like the taps are done with teflon coated wire ??
Teflon, although rated at 250 deg C.... is usually maxed out..

and

never run above 200 deg C. The teflon coated wires used for
tank coil taps will simply hold the heat in.... it won't be able
to escape. .... except for the hot connections at each end of

the

wire... where it terminates.

### On my 3CX-3000A7 HB lineear... I used wire for temp

taps

on the 3/8" tubing coil.... just for doing the MFJ test set
up.. with the usual resistor between anode and chassis.
Worked fine.... but when I replaced the temp small ga wire

with

3/4" wide strap.... the mfj was off.... turns out the temp

wire

taps had MORE inductance than the 3/4" wide strap. I had to
increase the tune C to compensate. Later on, I moved the

tap

again.... so I would end up with the desired uh..... with strap
being used.

### Now I never use wire for temp coil taps.

### I don't see any air being blown about the tank compartment..
for cooling tank coils, bandswitch, [looks sorta like a model 86]
etc.

### On Emtron's website... as of 2 mins ago... the DX-4 is NOT
listed anywhere !! Nor is it listed under "orders" or anywhere
else. However... do a google on dx-4... and loads of stuff
appears. I know it's an export only. Is it still being
made ????

## In any event.... the Fluke Mini 62 pistol grip IR
thermometer is an invaluable tool ! I USED to do it the old
way..... run a dead cxr.... get stuff hot.... with one finger
hovering 1" away from a tank coil..... shut off the cxr...
then start "touching" stuff..... and burning my finger.

With

HV every where... I highly DON'T reccomend this method....
hence the Fluke 62 .... faster, SAFER.. precise readings in
either C or F.

### Works on LC networks with NPO caps, coils etc. One would
think every commercial amp manufacturer would have a few on
hand.

Later... Jim VE7RF

Cheers, Dick
PA3DUV

----- Original Message -----
From: Peter Voelpel
To: ham_amplifiers@...
Sent: Friday, October 06, 2006 12:21 AM
Subject: RE: [ham_amplifiers] Re: Tank eff......WAS 3 - phase

HV

supply

Hi Dick,

200° on a iron powder toroid is pretty high.
That will raise your circuit L at least by 4%.
I replaced many low band toroidsin Command amps...

I wonder what the temperature of your 10m coil is at that 6KW

73
Peter

________________________________

From: ham_amplifiers@...

[mailto:ham_amplifiers@...]

On Behalf Of PA3DUV

The hottest point was the coil section INSIDE the toroid, 200C

+

was

measured

The 10-20-30 meter tank coil section went up to 130C

Will,

My problem is always that my fingers operating the keyboard or my mouth do
not consult with my brain. And yes, it gets worse with age.

-J

Hey all,

Has anyone had any luck repairing Cinch connectors on a Henry 3K Ultra? I am
tired of fooling with these. The females appear to have plenty of tension, but
no connute'n.

I'm not too happy, as they are no cinch to replace.

Thanks,
John, N9RF

Will,

Don't you hate when that happens?

John, N9RF

--- In ham_amplifiers@..., Frank Goenninger <frgo@...>
wrote:

Looking for a good LCR meter esp. for amp building i.e. for 1 to

30

MHz... Any recommendations that will not cause my XYL to throw me

out

of our house because it costs a month's salary? ;-)

Tnx es 73

de Frank DG1SBG

### I use a B+K 875-B available from Mouser in the USA...
and everywhere else. About aprx $169.00 to $179.00.
Measures down to 1/10 PF and also down to 1/10th uh.

### Have had mine since 1992.. built like a tank.. very rugged....
and dead on accurate.

### For 99% of most homebrewing etc.... you have to be able to
measure down to 1/10ths. We just wound a 4.9 uh coil for a
friend. We wanted 4.9 uh.... and not 5.0 uh.

## same deal with capacitance.

### IMO.... you are dead in the water without an LCR meter. My
#1 piece of test gear in the workshop !!

### BTW... I have new photo's up..... and will post one of the
LCR meter being used to find the 20-17-15 m taps on the HB 1/2"
tubing tank coil.... gotta find it 1st.

Later........Jim VE7RF

On Oct 7, 2006, at 3:44 AM, badgerscreek wrote:

Palstar has a new tuner on their web page for those who are interested.

Its rated at 10kw pep. To me it seems marginal to be rated at 10KW
pep with 6kv vacuum variables. Even 6kv at 1500 watt legal limit is
barely capable of handling many common antennas like doublets and
loops.

With a 1000-ohm antenna, 5kV-pk is 12,500w-rms.

The roller inductor is listed as having 10# wire. I would have
thought that a 1/2 inch flat strip roller inductor would have been
more appropiate.

Depends on operating Q, Greg. If the Palstar tuner is an L-network, #10 Cu should be okay for 10k of SSB -- unless the antenna Z is extraordinarily high -- such as with a Hertz antenna. (half-wave end- fed against ground).

However it may just be a line flattener and my judgement might be flawed!

Greg






Yahoo! Groups Links

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

Will,

craxd wrote:

Tony,

<snip>

"at 2000 RPM that would be 1000 sparks per minute or 16.666..."
No, for a 4 cylinder at 2000 RPM you would have 4000 sparks (pulses) per minute since 2 of the 4 cam lobes close the points twice per crank revolution. Since the crank is turning at 2000 RPM, the points close twice per crank revolution instead of 4 times. 4000 / 60 = 66.67 Hz.

You misquoted me out of context, Will...

I said:

"A single cylinder 4 cycle engine will fire only once per every 2
rotations. at 2000 RPM that would be 1000 sparks per minute or 16.666...
sparks per second."

I said SINGLE cylinder and you compared it directly to 4 cylinder.
<snip>

73, Tony W4ZT

In my opinion, the absolute best deal for the money is the L/C Meter IIB from Almost All Digital Electronics <>. It is very accurate and inexpensive. You can buy it as a kit or assembled. I use it all the time as do a lot of my friends.

73, Tony W4ZT

Frank Goenninger wrote:

Looking for a good LCR meter esp. for amp building i.e. for 1 to 30 MHz... Any recommendations that will not cause my XYL to throw me out of our house because it costs a month's salary? ;-)

Tnx es 73

de Frank DG1SBG

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

A four stroke motor fires once per two revolutions

Yup, the distributor has to turn at 1/2 the speed of the crank over
this (power and exhaust strokes). I had forgot about that too when I
wrote the first post. In a 4 cylinder like the example, 2 of the 4 cam
lobes close the points twice per crank revolution instead of 4 times.
Then you have two pulses or spraks per 1 revolution of the crank. See
my post to Tony for further explanation.

Best,

Will

craxd <craxd1@...> wrote: Yes, it does work that way! I

forgot to divide by 60 for seconds.

Every time the points close or one of the teeth on the toothed

magnet

passes by the hall effect sensor, that is 1 pulse per revolution of
the distributor. For points there is a rotating cam in the
distributor. The cam has lobes about its circumferance, and there's

a

lobe for every cylinder. As the cams lobe meets the points arm, it
presses against the arm and closes the contacts. The contacts

closing

connects the primary of the coil to ground closing the circuit. A
capacitor (condensor) is used with the points to make the coil fire
right for plugs (makes a LC circuit). Each time a lobe of the cam
closes the points, a plug fires, and that is 1 pulse per revolution
for the coil and circuit. For the electronic system, there's a gear
toothed type rotor where a magnet is on every tooth. There's 1 tooth
per cylinder. If a 4 cylinder, it has 4 teeth, an 8 cylinder 8

teeth.

Each time a magnet tooth passes by the hall effect device, a pulse

is

sent to a power transistor which is in series with the coils

primary,

and connects it to ground. This works similar to the mechanical
ignition using points. They also used a rotor with holes in it

similar

to an encoder. The holes in the rotor disc equaled the amount of
cylinders. They used a photo diode and a LED assembly to create the
pulse each time a hole in the rotor allowed the LED's light to pass
through to the photo diode and create a pulse. The ignition systems
now dont use any distributor cam, but use a computer to time the
firing. Anyhow, each time a spark plug fires, that is 1 pulse per
revolution for the coil. You take the pulses per minute and divide

by

60 to get the cycles per second or a number in Hertz (Hz).

The coil I figured below at 3200 pulses per minute would be 3200 /

60

= 53.33 Hz. In other words, first multiply the number of cylinders

by

the RPM, then divide by 60 to obtain the measurement in Hertz. For a

4

cylinder engine at 800 RPM; 800 RPM x 4 cylinders = 3200 ppm, then
3200 / 60 = 53.33 Hz. Good catch, I forgot this. This means that
standard transformer iron will work for the coils core.

I was wondering about this after my post when I read about a coils
construction which showed a laminated core made with silicon steel.

Thanks,

Will

--- In ham_amplifiers@..., "K1PT" <k1pt@> wrote:

Will,
Divide RPM (per minute!) by 60 to get Hz. I'm not sure I

understand the rest of the discussion, though.

Paul K1PT
----- Original Message -----
From: craxd
To: ham_amplifiers@...
Sent: Thursday, October 05, 2006 11:40 PM
Subject: [ham_amplifiers] Re: Hi-pot tester


Old coils that ran off points could have a frequency thats
derived from a RPM of 800 to 2000+ RPM or so. The new ones
without points use a pulse from a toothed rotating magnets
and a hall effect sensor to fire a power switching transistor,
but still use the RPM of the engine to turn the magnets. The
RPM is multiplied by the number of cylinders to obtain the
frequency of the coil. A 4 cyl. engine idling at 800 RPM would
have a coil frequency of 3200 Hz. So it's according to what
the engines RPM is. The lowest frequency is what you design around
as anything higher, the flux density actually drops. It's
also according to the material of the core. Some iron (silicon
steel), according to the type and thickness, can be ran up to 10
kHz according to the steel manufacturers. However, lets take a
4 cyl at 2000 RPM, that would be a frequency of 8 kHz. An 8 cyl
engine would be 16 kHz at 2000 RPM. The thing is, a motors RPM
can be revved on up, so the frequency can vary even higher. Some
of the new coils have an EI core shape, but to my opinion,
they're ferrite like a TV's flyback transformer. You can't really
see what it is as they're enclosed in plastic. Anyhow, this can
give you an idea of what the operating frequency is for the coil.

Best,

Will

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

Hi,Guillermo,
I think your square wave generator's freqence is too high?the
ignition automotive coils's is iron not ferrite, the frequence
must below kilo hertz
73! Hsu


u may be in the good direction; I did not tried with TV flyback
transformers, but did once some experiments with old ignition

automotive

coils, excited with a square wave generator and a darlington

transistor

amplifier. I could never get more than 400 volts pk-pk. With 13.

8V

supply.

The circuit was not optimized also due to lack of time for

another

tasks, but

I think one could get better results.
More experimentation is in order here.

Best regards
Guillermo - LU8EYW.

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Tony,

Your correct about this too! When I wrote that, I not only forgot
about dividing by 60 to get the cycles, but that the distributor
turns at 1/2 revolution per 1 revolution of the crank. In other
words, the crank turns 2 times as fast as the distributor so one
must divide the RPM by 2 (use 1/2 the cylinders or cam lobes),
then divide by 60 get the cycles. So, 2 of the 4 cam lobes in a
4 cylinder will close the points per each revolution of the
crank. That means 2 pulses (sparks) per crank revolution. At 800
RPM (about idle speed), we would have 1600 pulses instead of
3200. 1600 / 60 = 26.67 Hz. At say 2000 RPM which is about
running speed, there would be 4000 pulses instead of 8000.
4000 / 60 = 66.67 Hz. A coil using silicon steel will handle
this. Especially when the engine will not be at idle speed as
much as running speed. The only thing is the core would have
to be larger at 26.67 Hz than at 66.67 Hz. One always designs
a transformer around the lowest frequency it will see.


"at 2000 RPM that would be 1000 sparks per minute or 16.666..."

No, for a 4 cylinder at 2000 RPM you would have 4000 sparks
(pulses) per minute since 2 of the 4 cam lobes close the points
twice per crank revolution. Since the crank is turning at 2000
RPM, the points close twice per crank revolution instead of 4
times. 4000 / 60 = 66.67 Hz.

Say one was revved the engine up to 4000 RPM. The points would
close 2 times per crank revolution which would be
4000 x 2 = 8000 times. 8000 / 60 = 133.33 Hz.

Quote from webpage;

"It is 30 degrees of crank advance, because the distributor turns at
half the speed of the crank, and whatever you do with the distributor,
in degrees, is doubled on the crank".

At:

Shows cam for a 6 cylinder;



Other links;



,
2021,DIY_13677_2271388,00.html

Best,

Will

--- In ham_amplifiers@..., Tony King - W4ZT <w4zt-060920@.
..> wrote:

Will,

A single cylinder 4 cycle engine will fire only once per every 2
rotations. at 2000 RPM that would be 1000 sparks per minute or 16.

666...

sparks per second. Increase the number of cylinders and you will
increase the number of sparks but even with 8 the number of sparks

per

second will not be very high. The cylinders fire sequentially

through 2

rotations. 8*16.666...=133.333... sparks per second.

I don't think that a spark coil acts like an ordinary transformer

which

you can drive with AC and expect to get the same output. It requires

the

collapse of the field to cause the high energy spark in a

conventional

one so it would be very difficult to get the same reaction from any
conventional drive unless it provided a high current to build the

field.

Seems it would require a square wave of extremely low impedance and
proper repetition rate. Then the output would be very short duration
ringing pulses.

73, Tony W4ZT

craxd wrote:

Old coils that ran off points could have a frequency thats
derived from a RPM of 800 to 2000+ RPM or so. The new ones
without points use a pulse from a toothed rotating magnets
and a hall effect sensor to fire a power switching transistor,
but still use the RPM of the engine to turn the magnets. The
RPM is multiplied by the number of cylinders to obtain the
frequency of the coil. A 4 cyl. engine idling at 800 RPM would
have a coil frequency of 3200 Hz. So it's according to what
the engines RPM is. The lowest frequency is what you design around
as anything higher, the flux density actually drops. It's
also according to the material of the core. Some iron (silicon
steel), according to the type and thickness, can be ran up to 10
kHz according to the steel manufacturers. However, lets take a
4 cyl at 2000 RPM, that would be a frequency of 8 kHz. An 8 cyl
engine would be 16 kHz at 2000 RPM. The thing is, a motors RPM
can be revved on up, so the frequency can vary even higher. Some
of the new coils have an EI core shape, but to my opinion,
they're ferrite like a TV's flyback transformer. You can't really
see what it is as they're enclosed in plastic. Anyhow, this can
give you an idea of what the operating frequency is for the coil.

Best,

Will


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

Hi,Guillermo,
I think your square wave generator's freqence is too high?the
ignition automotive coils's is iron not ferrite, the frequence
must below kilo hertz
73! Hsu


u may be in the good direction; I did not tried with TV flyback
transformers, but did once some experiments with old ignition

automotive

coils, excited with a square wave generator and a darlington

transistor

amplifier. I could never get more than 400 volts pk-pk. With 13.

8V

supply.

The circuit was not optimized also due to lack of time for

another

tasks, but

I think one could get better results.
More experimentation is in order here.

Best regards
Guillermo - LU8EYW.

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A four stroke motor fires once per two revolutions

craxd wrote:

Yes, it does work that way! I forgot to divide by 60 for seconds.
Every time the points close or one of the teeth on the toothed magnet
passes by the hall effect sensor, that is 1 pulse per revolution of
the distributor. For points there is a rotating cam in the
distributor. The cam has lobes about its circumferance, and there's a
lobe for every cylinder. As the cams lobe meets the points arm, it
presses against the arm and closes the contacts. The contacts closing
connects the primary of the coil to ground closing the circuit. A
capacitor (condensor) is used with the points to make the coil fire
right for plugs (makes a LC circuit). Each time a lobe of the cam
closes the points, a plug fires, and that is 1 pulse per revolution
for the coil and circuit. For the electronic system, there's a gear
toothed type rotor where a magnet is on every tooth. There's 1 tooth
per cylinder. If a 4 cylinder, it has 4 teeth, an 8 cylinder 8 teeth.
Each time a magnet tooth passes by the hall effect device, a pulse is
sent to a power transistor which is in series with the coils primary,
and connects it to ground. This works similar to the mechanical
ignition using points. They also used a rotor with holes in it similar
to an encoder. The holes in the rotor disc equaled the amount of
cylinders. They used a photo diode and a LED assembly to create the
pulse each time a hole in the rotor allowed the LED's light to pass
through to the photo diode and create a pulse. The ignition systems
now dont use any distributor cam, but use a computer to time the
firing. Anyhow, each time a spark plug fires, that is 1 pulse per
revolution for the coil. You take the pulses per minute and divide by
60 to get the cycles per second or a number in Hertz (Hz).

The coil I figured below at 3200 pulses per minute would be 3200 / 60
= 53.33 Hz. In other words, first multiply the number of cylinders by
the RPM, then divide by 60 to obtain the measurement in Hertz. For a 4
cylinder engine at 800 RPM; 800 RPM x 4 cylinders = 3200 ppm, then
3200 / 60 = 53.33 Hz. Good catch, I forgot this. This means that
standard transformer iron will work for the coils core.

I was wondering about this after my post when I read about a coils
construction which showed a laminated core made with silicon steel.

Thanks,

Will


--- In ham_amplifiers@..., "K1PT" <k1pt@...> wrote:

Will,
Divide RPM (per minute!) by 60 to get Hz. I'm not sure I

understand the rest of the discussion, though.

Paul K1PT
----- Original Message -----
From: craxd
To: ham_amplifiers@...
Sent: Thursday, October 05, 2006 11:40 PM
Subject: [ham_amplifiers] Re: Hi-pot tester


Old coils that ran off points could have a frequency thats
derived from a RPM of 800 to 2000+ RPM or so. The new ones
without points use a pulse from a toothed rotating magnets
and a hall effect sensor to fire a power switching transistor,
but still use the RPM of the engine to turn the magnets. The
RPM is multiplied by the number of cylinders to obtain the
frequency of the coil. A 4 cyl. engine idling at 800 RPM would
have a coil frequency of 3200 Hz. So it's according to what
the engines RPM is. The lowest frequency is what you design around
as anything higher, the flux density actually drops. It's
also according to the material of the core. Some iron (silicon
steel), according to the type and thickness, can be ran up to 10
kHz according to the steel manufacturers. However, lets take a
4 cyl at 2000 RPM, that would be a frequency of 8 kHz. An 8 cyl
engine would be 16 kHz at 2000 RPM. The thing is, a motors RPM
can be revved on up, so the frequency can vary even higher. Some
of the new coils have an EI core shape, but to my opinion,
they're ferrite like a TV's flyback transformer. You can't really
see what it is as they're enclosed in plastic. Anyhow, this can
give you an idea of what the operating frequency is for the coil.

Best,

Will

--- In ham_amplifiers@..., "Hsu" <Jbenson@> wrote:
>
> Hi,Guillermo,
> I think your square wave generator's freqence is too high?the
> ignition automotive coils's is iron not ferrite, the frequence
> must below kilo hertz
> 73! Hsu
>
>
> u may be in the good direction; I did not tried with TV flyback
> transformers, but did once some experiments with old ignition
automotive
> coils, excited with a square wave generator and a darlington
transistor
> amplifier. I could never get more than 400 volts pk-pk. With 13.

8V

supply.
> The circuit was not optimized also due to lack of time for

another

tasks, but
> I think one could get better results.
> More experimentation is in order here.
>
> Best regards
> Guillermo - LU8EYW.
>
> Recent Activity
> 17New Members
> 1New Files
> Visit Your Group
> Y! GeoCities
> Share Your Resume
> Show off your
> talent and skills.
> Y! Toolbar
> Get it Free!
> easy 1-click access
> to your groups.
> Yahoo! Groups
> Start a group
> in 3 easy steps.
> Connect with others..
>

Will,

A single cylinder 4 cycle engine will fire only once per every 2 rotations. at 2000 RPM that would be 1000 sparks per minute or 16.666... sparks per second. Increase the number of cylinders and you will increase the number of sparks but even with 8 the number of sparks per second will not be very high. The cylinders fire sequentially through 2 rotations. 8*16.666...=133.333... sparks per second.

I don't think that a spark coil acts like an ordinary transformer which you can drive with AC and expect to get the same output. It requires the collapse of the field to cause the high energy spark in a conventional one so it would be very difficult to get the same reaction from any conventional drive unless it provided a high current to build the field. Seems it would require a square wave of extremely low impedance and proper repetition rate. Then the output would be very short duration ringing pulses.

73, Tony W4ZT

craxd wrote: