2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V of
pulses of repeat 3uS for the gate and about 3V ringing swing on the output
to the first step up transformer. I assume that is as to be expected, never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final stage
(unreadable marking) thyristor discharges that supply into the second step
up transformer, but of course not even enough to get a glow on a 110V neon.
Doubling the C setting the 3uS pulses, to give longer repeat rate and that
intermediary voltage rises to about 3V but still not enough for any proper
final output. Adding more C and DC is then much less than 3V.
What would people expect the intermediary DC to be? obviously higher than
12V battery supply
Next stage would be disconnect the thyristor if that should be working but
leaky and draining the intermediary DC but any other ideas? Would explain
why the printing is very indistinct I suppose.
DC ohms of the airgap type transformers are
intermediary 0.1R//10.6R
HV 0.3R//29R which seem reasonable, ie not major shorted turns if any

Meat Plow wrote in message
...
On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" wrote:

2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant
corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double
diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V
of
pulses of repeat 3uS for the gate and about 3V ringing swing on the
output
to the first step up transformer. I assume that is as to be expected,
never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final stage
(unreadable marking) thyristor discharges that supply into the second
step
up transformer, but of course not even enough to get a glow on a 110V
neon.
Doubling the C setting the 3uS pulses, to give longer repeat rate and
that
intermediary voltage rises to about 3V but still not enough for any
proper
final output. Adding more C and DC is then much less than 3V.
What would people expect the intermediary DC to be? obviously higher than
12V battery supply
Next stage would be disconnect the thyristor if that should be working
but
leaky and draining the intermediary DC but any other ideas? Would explain
why the printing is very indistinct I suppose.
DC ohms of the airgap type transformers are
intermediary 0.1R//10.6R
HV 0.3R//29R which seem reasonable, ie not major shorted turns if any


I would expect the output to be at fault when you take into
consideration all the short circuits electric fencing can encounter.

I've disconnected the HV section and no difference. The o/p of the
intermediate is 4V pk-pk pulses with designed 3uS osc i/p. Barely enough to
exceed the bank of 6 seriesed rectifier diodes . Inductances of the
intermediate Tr are 0.1mH and 84mH . i'm wondering if there is shorted
turns, will try and find some SMPS to try in reverse.
The output Tr is E-I iron cored not HF on closer looking

On Jul 7, 6:46*am, "N_Cook" wrote:
2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V of
pulses of repeat 3uS for the gate and about 3V ringing swing on the output
to the first step up transformer. I assume that is as to be expected, never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final stage
(unreadable marking) thyristor discharges that supply into the second step
up transformer, but of course not even enough to get a glow on a 110V neon.

nesesu wrote in message
...
On Jul 7, 6:46 am, "N_Cook" wrote:
2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double
diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V of
pulses of repeat 3uS for the gate and about 3V ringing swing on the output
to the first step up transformer. I assume that is as to be expected,
never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final stage
(unreadable marking) thyristor discharges that supply into the second step
up transformer, but of course not even enough to get a glow on a 110V
neon.
Doubling the C setting the 3uS pulses, to give longer repeat rate and that
intermediary voltage rises to about 3V but still not enough for any proper
final output. Adding more C and DC is then much less than 3V.
What would people expect the intermediary DC to be? obviously higher than
12V battery supply
Next stage would be disconnect the thyristor if that should be working but
leaky and draining the intermediary DC but any other ideas? Would explain
why the printing is very indistinct I suppose.
DC ohms of the airgap type transformers are
intermediary 0.1R//10.6R
HV 0.3R//29R which seem reasonable, ie not major shorted turns if any

Sounds like the unit may have been hit by a lightning surge. I have
seen a few and usually all the electronic parts are blown as well at
the transformer winding insulation punctured.
To your question of intermediate voltage, I would suspect something in
the 50-100V range. I imagine that there is a storage cap since your
description sounds like a C-D circuit, so one would expect the
intermediate voltage to be around 60% of the cap voltage rating, if it
is an electrolytic.
Neil S.

&&&&&&&

I'd not thought of that route, will desolder the C, script on the wrong
side. I'd expect the dual monostable IC to be knocked out with lightning

On Jul 7, 8:46*am, "N_Cook" wrote:
2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V of
pulses of repeat 3uS for the gate and about 3V ringing swing on the output
to the first step up transformer. I assume that is as to be expected, never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final stage
(unreadable marking) thyristor discharges that supply into the second step
up transformer, but of course not even enough to get a glow on a 110V neon.

On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" put
finger to keyboard and composed:

What would people expect the intermediary DC to be? obviously higher than
12V battery supply

B20 Dry Battery Energiser:
http://www.forcefield-uk.co.uk/b20.htm

If the above is your electric fence device, then the Stored Joules
rating of 0.2J should enable you to calculate the voltage across the
HV capacitor.

E = 1/2 x C x V^2

so V = sqrt (2 x 0.2 / C)

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Franc Zabkar wrote in message
...
On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" put
finger to keyboard and composed:

What would people expect the intermediary DC to be? obviously higher than
12V battery supply

B20 Dry Battery Energiser:
http://www.forcefield-uk.co.uk/b20.htm

If the above is your electric fence device, then the Stored Joules
rating of 0.2J should enable you to calculate the voltage across the
HV capacitor.

E = 1/2 x C x V^2

so V = sqrt (2 x 0.2 / C)

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

The cap is 1uF , 280V ac rating. From the .5*C*V*V that comes to 630V, so
something awry there.
No more than 250V m 60% of likely DC rating, and I would have thought more
like an equal split between 12V and 1800V so about 150V, transformers are
much the same size if that is anything to go by

If I ever get this thing working properly , how to check the average current
drain?
I am thinking 12V supply - ammeter - bank of 20V Cs summing to about 0.1F
- fencer unit

that is a current limited 12V supply , not a car battery of course

On Thu, 8 Jul 2010 08:24:40 +0100, "N_Cook" put
finger to keyboard and composed:

Franc Zabkar wrote in message
.. .
On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" put
finger to keyboard and composed:

What would people expect the intermediary DC to be? obviously higher than
12V battery supply

B20 Dry Battery Energiser:
http://www.forcefield-uk.co.uk/b20.htm

If the above is your electric fence device, then the Stored Joules
rating of 0.2J should enable you to calculate the voltage across the
HV capacitor.

E = 1/2 x C x V^2

so V = sqrt (2 x 0.2 / C)

The cap is 1uF , 280V ac rating. From the .5*C*V*V that comes to 630V, so
something awry there.
No more than 250V m 60% of likely DC rating, and I would have thought more
like an equal split between 12V and 1800V so about 150V, transformers are
much the same size if that is anything to go by

It may appear counterintuitive, but a rating of 280VAC/630VDC for a
metallised polypropylene or polyester capacitor is not uncommon.

http://www.aerovox.com/pdf/DC_Film_Axials.pdf
http://www.ibselectronics.com/pdf/pa...capacitors.pdf
http://www.descartes.com.tw/product/...WIMA_MKP_4.pdf

See the Axial Metallized Polypropylene Capacitors on page 10 of the
first PDF.

In particular, there is a 1uF, 280VAC/630VDC cap, p/n ARPM10563KYUKZZ.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Meat Plow wrote in message
...
On Thu, 8 Jul 2010 08:54:46 +0100, "N_Cook" wrote:

If I ever get this thing working properly , how to check the average
current
drain?
I am thinking 12V supply - ammeter - bank of 20V Cs summing to about
0.1F
- fencer unit


Find a cow, sheep or horse willing to test it.

I don't think asking one "hoo moony mooliemoomps dooze this moozapper gizmoo
take" would get very far

On Thu, 8 Jul 2010 08:24:40 +0100, "N_Cook" put
finger to keyboard and composed:

The cap is 1uF , 280V ac rating. From the .5*C*V*V that comes to 630V, so
something awry there.
No more than 250V m 60% of likely DC rating, and I would have thought more
like an equal split between 12V and 1800V so about 150V, transformers are
much the same size if that is anything to go by

If the device is designed to output its rated energy over a 9V-12V
supply range, then one would expect that the dump capacitor's voltage
would be regulated. Otherwise the variation in the stored energy would
be (12/9)^2 = 1.8X.

Is there any voltage feedback from the dump cap back to its charge
controller? I'd expect to see a resistive potential divider feeding
one input of an error amp (comparator?), and maybe a 5V or 2.5V
reference on the other input. You may be able to compute the voltage
from the resistance values.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Franc Zabkar wrote in message
...
On Thu, 8 Jul 2010 08:24:40 +0100, "N_Cook" put
finger to keyboard and composed:

The cap is 1uF , 280V ac rating. From the .5*C*V*V that comes to 630V, so
something awry there.
No more than 250V m 60% of likely DC rating, and I would have thought
more
like an equal split between 12V and 1800V so about 150V, transformers are
much the same size if that is anything to go by

If the device is designed to output its rated energy over a 9V-12V
supply range, then one would expect that the dump capacitor's voltage
would be regulated. Otherwise the variation in the stored energy would
be (12/9)^2 = 1.8X.

Is there any voltage feedback from the dump cap back to its charge
controller? I'd expect to see a resistive potential divider feeding
one input of an error amp (comparator?), and maybe a 5V or 2.5V
reference on the other input. You may be able to compute the voltage
from the resistance values.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.


There is a chain of 3.3M resistors for feedback , I suspect it would change
the 1.5KHz multivibrator rather than the 300KHz one. There is also the 1 to
2 second repetition cycling, perhaps 3 multivibrator package, also
unreadable marking

On Fri, 9 Jul 2010 08:45:56 +0100, "N_Cook" put
finger to keyboard and composed:

There is a chain of 3.3M resistors for feedback , I suspect it would change
the 1.5KHz multivibrator rather than the 300KHz one. There is also the 1 to
2 second repetition cycling, perhaps 3 multivibrator package, also
unreadable marking

I would expect that the multivibrator would have an internal reference
voltage which it would compare against the voltage on the resistor at
the bottom end of the potential divider. The IC's reference voltage
may appear on one of its pins.

I would locate where the divider feeds into the IC, and determine the
values of all the resistances in the chain. Then measure the voltages
on the pins on either side of the feedback pin. If you can supply this
information, then perhaps it will help ascertain the capacitor
voltage.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

"N_Cook" wrote in message
...
2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double
diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V of
pulses of repeat 3uS for the gate and about 3V ringing swing on the output
to the first step up transformer. I assume that is as to be expected,
never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final stage
(unreadable marking) thyristor discharges that supply into the second step
up transformer, but of course not even enough to get a glow on a 110V
neon.
Doubling the C setting the 3uS pulses, to give longer repeat rate and that
intermediary voltage rises to about 3V but still not enough for any proper
final output. Adding more C and DC is then much less than 3V.
What would people expect the intermediary DC to be? obviously higher than
12V battery supply
Next stage would be disconnect the thyristor if that should be working but
leaky and draining the intermediary DC but any other ideas? Would explain
why the printing is very indistinct I suppose.
DC ohms of the airgap type transformers are
intermediary 0.1R//10.6R
HV 0.3R//29R which seem reasonable, ie not major shorted turns if any



Hi,

I found this schematic (circuit diagram) somewhere on the net, is it
anything like your one ?

http://www.electro-tech-online.com/a...ctricfence.jpg

Ian.

Ian French wrote in message
...

"N_Cook" wrote in message
...
2 stage derivation of (should be) 1800V pulses.
Fence had failure in the first stage probably due to intermittant
corroded
battery supply contact.
Anyway the 15A 60V 8N06 powerFET blew along with an associated double
diode
BAV23.
Replaced both and works to some extent. This FET has plenty of drive 5V
of
pulses of repeat 3uS for the gate and about 3V ringing swing on the
output
to the first step up transformer. I assume that is as to be expected,
never
having the chance to see hot-side SMPS drive scope traces.
But rectified output only climbs to about 1V of DC before the final
stage
(unreadable marking) thyristor discharges that supply into the second
step
up transformer, but of course not even enough to get a glow on a 110V
neon.
Doubling the C setting the 3uS pulses, to give longer repeat rate and
that
intermediary voltage rises to about 3V but still not enough for any
proper
final output. Adding more C and DC is then much less than 3V.
What would people expect the intermediary DC to be? obviously higher
than
12V battery supply
Next stage would be disconnect the thyristor if that should be working
but
leaky and draining the intermediary DC but any other ideas? Would
explain
why the printing is very indistinct I suppose.
DC ohms of the airgap type transformers are
intermediary 0.1R//10.6R
HV 0.3R//29R which seem reasonable, ie not major shorted turns if any



Hi,

I found this schematic (circuit diagram) somewhere on the net, is it
anything like your one ?


http://www.electro-tech-online.com/a...ects-design-id
eas-reviews/4007d1108193301-need-help-developing-electric-fencing-my-farm-el
ectricfence.jpg

Ian.




The 'IV' and HV stage is very similar, this one has a lot of SM so a bit
more distributed for the higher voltages, ie tripling up of diodes and Rs

Do you have the URL of the text relating to that pic
Search on that site just enigmatically/awkwardly/insultingly returns
"The answer given for the random question was incorrect."

Googled for it
http://www.electro-tech-online.com/e...ideas-reviews/
13848-need-help-developing-electric-fencing-my-farm.html

On Sat, 10 Jul 2010 15:42:04 +0100, "N_Cook" put
finger to keyboard and composed:

Do you have the URL of the text relating to that pic

That Dick Smith kit was based on Silicon Chip Magazine's April 1999
High Power Electric Fence Controller.

FWIW, here is the PCB and front panel label:
http://www.siliconchip.com.au/cms/at...99&month=April

If you can't locate the technical description on SC's web site, let me
know and I'll look through my paperwork.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.