[Amps] questions about hi pot tester

[jeremy-ca]

For TX tube testing Ive built a few using neon sign transformers and will 
get up to around 15 KV.

Another version built by many is here:

http://www.somis.org/BVT.html

Now that Im playing around with AM again Ive found a hi pot to be a very 
useful instrument to evaluate ancient tubes.

Carl
KM1H




----- Original Message ----- 
From: "Dan Evans" <dan.evans at insightbb.com>
To: "Amps Reflector" <amps at contesting.com>
Sent: Sunday, January 06, 2008 9:45 AM
Subject: Re: [Amps] questions about hi pot tester


> 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
> -- 
> K9ZF /R no budget Rover ***QRP-l #1269
> Check out the Rover Resource Page at: <http://www.qsl.net/n9rla>
> List Administrator for: InHam+grid-loc+ham-books
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>
>
>
> TexasRF at 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 at 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 at yahoo.com>
>> To: "Steve Katz"  <stevek at jmr.com>
>> Cc: <Amps at 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 at 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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>>> Amps at contesting.com
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>>>
>>>
>>
>>
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