Tried to post this once, but my message was bounced...
If anyone is looking at building hi-pots, I have quite a few of these
microwave oven parts on hand.
The transformers would be a bit expensive to ship, but I also have lots
of diodes and caps.
I'm open to reasonable offers, or even trades:-)
73
Dan
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TexasRF@aol.com wrote:
>
> 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
>>
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>>
>>
>
>
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