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
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
No manufacturer information aailable??
>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
>Franc Zabkar <fza...@iinternode.on.net> wrote in message
>news:e8u936t7msgm25002...@4ax.com...
>> On Wed, 7 Jul 2010 14:46:36 +0100, "N_Cook" <div...@tcp.co.uk> 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/wima/wima_pulse_capacitors.pdf
http://www.descartes.com.tw/product/wima/wima_pdf/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.
I don't think asking one "hoo moony mooliemoomps dooze this moozapper gizmoo
take" would get very far
>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.
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
>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.
Hi,
I found this schematic (circuit diagram) somewhere on the net, is it
anything like your one ?
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."
>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/attachments/show.html?year=1999&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.