Didn't figure that info really mattered. I was looking for an exact or
equivalent. I realize its old stock; but if it really matters it is out of
the main portion of an electric fence circuit board.
You have reluctantly now told us that the item containing the
capacitor is an electric fence charger but you fail to give any brand
or model details. All one can do with what you have provided is to
make an intelligent guess.
If I had posted a request that said I wanted a fuel pump for my car in
order to repair it, then this would have been quite rightly greeted
with derision. The make, model, year etc would be mandatory
information to supply in order to get any help and your query is in
the same category.
Given the probable age of your fence charger (or the capacitor in
question) plus the fact that the manufacturer of that capacitor hasn't
been in existence since about 1989 then the likelihood of getting the
same unit is highly improbable. The fact that the capacitor is of
Australian origin suggests that the fence charger is also Australian
made as well, but you haven't provided any details related to the
manufacturer. Since Plessey Ducon no longer exists, and the data on
this particular capacitor is no longer available, then the more
information you provide the better able anyone is to suggest an
alternative.
The application to which a capacitor is put is extremely relevant when
trying to determine a replacement. The only flexible wire leaded
cylindrical polypropylene capacitors made by Plessey Ducon were
produced for the power industry for flourescent lighting power factor
correction and motor start/run applications, so the unit you are
trying to replace is most likely one of those, but just why it is
marked with a dc voltage rating is not clear. These capacitors were
commonly used in strobe lighting and fence charger applications.
I am guessing that the capacitor is used as the charge storage
capacitor which is then dumped periodically into the output
transformer of your fence charger. Depending upon the output voltage
of the dc-dc converter in the charger, and the turns ratio of the
output transformer, we can only make a guess as to the ac voltage
rating of a similar capacitor manufactured currently.
Around the mid 80's the Australian standard AS3129 for fence chargers
specified that the maximum voltage allowed to be connected to a fence
was 5kV into a 1 megohm load, plus other pulse timing and allowable
current details. Also, there was only one Australian manufacturer that
I am aware of (Jones Transformers model JT349) making an output
transformer specifically for fence chargers and this had a ratio of
about 1:20(P:S). This allowed for a dc-dc converter having 250Vdc as
the output voltage to charge the storage capacitor.
Not having any specific details of your fence charger all I can say is
that a circuit design I have to hand with these same specifications
and using this output transformer specifies a metallized paper or
polypropylene capacitor specified for high current pulse operation,
rated at 250Vac - 440Vac and between the values of 6.0 - 25uF. Such
capacitors will safely handle dc voltages from 400V and above, which
your dc-dc converter is unlikely to produce.
Here is some data on current Australian capacitors similar to the one
you are looking for
http://www.tridonicatco.com.au/Medien/cat0304_au/Capacito.pdf
All you have to do now is find something similar where you are located
so surely you are capable of doing that.
