One useful source of high voltage parts is from old microwave ovens. In
particular, the power transformer, filter capacitors and diodes are plentiful
and
cheap on Ebay.
The filter caps are typically .95 microfarads and will easily handle more
than 6500vdc. One transformer, four diodes in a 4X multplier and four
capacitors
will generate approximately 13kv.
To prevent damage to the component under test, the current should be
limited. One very easy way to do that is by using a Tripplett 630, set for 6kv,
in
series with the output. The 630 will indicate full scale at a current flow of
60 microamps and what ever the reading is in volts should be deducted from the
power supply voltage reading to determine the actual breakdown voltage.
I use a small 2 amp Variac to vary the primary voltage, allowing output
voltage to be set over a range of 0 to 13kv. At greater than 6kv, I use two 630
meters in series and add their readings to measure the output voltage.
Yes it is a kludge, but it does work quite well, especially considering the
cost.
73,
Gerald K5GW
In a message dated 1/3/2008 2:37:58 P.M. Central Standard Time,
barrie@centric.net writes:
Commander!
I was in much the same position, in that I had gathered almost all that I
needed to build a hipot, but the filter caps kept getting away, especially
price-wise.
I ended up buying a commercial unit on EBay, in the "Industrial Electronics"
section.
Continusously variable voltage from zero to 15 KV, variable load from 2
microamps on up, two big meters and looks as if it had never been used.
$100.00, shipping included.
73, Barrie, W7ALW
----- Original Message -----
From: "Commander John" <crazytvjohn@yahoo.com>
To: "Steve Katz" <stevek@jmr.com>
Cc: <Amps@contesting.com>
Sent: Thursday, January 03, 2008 1:18 PM
Subject: Re: [Amps] questions about hi pot tester
> The application is to ham radio related stuff. Not commercial. I do not
know what I may need to test in the future, so I do not know what to get in
a tester.
>
> john w9zy
>
> Steve Katz <stevek@jmr.com> wrote:
> What's the application?
>
> A lot of off-the-shelf hipot testers for consumer electronic equipment
> stop at 6kVdc (because that's the limit of the requirement for
> compliance testing on a 240V circuit) and that's not nearly high enough
> voltage to test, say, a high power transmitting tube.
>
> Are you looking to do compliance testing, which requires a stipulated
> ramp time, dwell time and leakage limit? Or just to see where stuff
> flashes over? How high a voltage?
>
> WB2WIK/6
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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