Vintage Kv meter.

Thread Starter

Rufuss

Joined Apr 19, 2022
8
Good afternoon.
Following on from an earlier post of mine concerning repair and upgrade of a fence energiser, which is now working perfectly thanks to some input from this forum, I’d like to ask another question concerning an old vintage Kv meter. Could this be used as a fence tester or am I missed something…
 

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ronsimpson

Joined Oct 7, 2019
2,058
I think the meter dose not directly read 20KV but needs an external resistor. The first clue is the terminals do not look like they can take 20kv. The second clue is on the face of the meter.
1652187250233.png
 

Ya’akov

Joined Jan 27, 2019
5,656
It can probably be used but fundamentally that is not a "KV meter", it is actually an ammeter with a full scale deflection of 100μA and a scale in KV.

You will need the proper resistor to make the scale mean anything.
 

dendad

Joined Feb 20, 2016
4,134
Probably not directly.
You may be able to use a rectifier from a microwave oven, and suitably rated high voltage capacitor to drive the meter, but I think you will also need external multiplier resistors as I doubt they are actually in the meter.
It looks to be a 100uA 1Kohm movement so that means a 200Mohm resistor string needed.
The fence pulse is very narrow and that makes it pretty hard to measure.
Probably connect the rectifier to the capacitor without the meter and let the fence zapper run for a while to charge up, then measure it.
Be careful as the cap will hold lots of volts.
A better way is to buy a commercial test device. For instance, .....
https://www.amazon.com.au/dp/B000HH...eywords=electric fence tester&geniuslink=true

But a DIY one like from this circuit will be easier.
1652187502241.png
Once again, be careful. Build it in a well insulated plastic case.
 

Thread Starter

Rufuss

Joined Apr 19, 2022
8
Probably not directly.
You may be able to use a rectifier from a microwave oven, and suitably rated high voltage capacitor to drive the meter, but I think you will also need external multiplier resistors as I doubt they are actually in the meter.
It looks to be a 100uA 1Kohm movement so that means a 200Mohm resistor string needed.
The fence pulse is very narrow and that makes it pretty hard to measure.
Probably connect the rectifier to the capacitor without the meter and let the fence zapper run for a while to charge up, then measure it.
Be careful as the cap will hold lots of volts.
A better way is to buy a commercial test device. For instance, .....
https://www.amazon.com.au/dp/B000HHJIWW?tag=farmhacker-22&keywords=electric fence tester&geniuslink=true

But a DIY one like from this circuit will be easier.
View attachment 266847
Once again, be careful. Build it in a well insulated plastic case.
Thanks for the info
I have a soft spot for these old units, or anything retro like this…..think it comes from watching “Carry on Screaming” and seeing those monsters wake up to a strong electrical charge….or is it just me?
 

dendad

Joined Feb 20, 2016
4,134
No, it is not just you.
I think quite a lot of us here love the old gear. At my last Ham radio club meeting, there was a real old radio tube, I forget the number, but 4 pin base, a top cap and a side grid cap.Very nice!

EDIT: I remembered the number, 808, and found a picture like it...
808.jpg
 
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