If I remember correctly, the Jennings test procedure uses AC and they
test by applying voltage for a period, during which arcing can happen
and then getting no arcs for a subsequent period - can't recall if it's
a minute or an hour...
I'm seeing leakage current as distinct from arcing.
Steve
Carl wrote:
> This thread brings up a question Ive had for awhile. When hi potting a
> vacuum variable is it better to use AC or DC for the cooking?
>
> Ive a surplus shop commercial unit that goes to 15 kV in 3 ranges and
> with selectable current limiting. I havent used it for anything but
> testing transformer insulation so far.
>
> Carl
> KM1H
>
> ----- Original Message ----- From: "Randall, Randy"
> <Randy.Randall@healthall.com>
> To: "'Steve'" <g8gsq@f2s.com>; <amps@contesting.com>
> Sent: Friday, September 18, 2009 9:51 AM
> Subject: Re: [Amps] Vacuum variable hipot
>
>
>> You should really see 0uA. Run it through its range and stop on the
>> positions that have leakage. Drop it to 4 KV and let it cook. You
>> might be able to effect a repair if it is gas as the arc will getter
>> to some extent or the arc may help clear the leakage path. It could
>> very well make it worse. You have nothing to lose at this point.
>>
>> Randy AB9GO
>>
>> -----Original Message-----
>> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
>> On Behalf Of Steve
>> Sent: Friday, September 18, 2009 7:03 AM
>> To: amps@contesting.com
>> Subject: [Amps] Vacuum variable hipot
>>
>> I have a Jennings UCSL1000 - 1000pF, 5kV cap. If I put 5kV dc across it
>> and run it through its tuning range, the leakage current is sometimes
>> zero but fluctuates and there are places where the current leaps up to
>> 50uA. At those points the current falls to zero if the voltage is
>> reduced to around 4kV, although I have heard a couple of arc 'pops' from
>> it sitting there at 4kV.
>>
>> At other settings where the current is lower, 5uA or less, the leakage
>> dies away to zero if I leave it sitting there for a while.
>>
>> Is this normal behaviour? Is this one a duffer?
>>
>> Thanks,
>>
>> Steve
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