[AMPS] Re: High voltage tester 0-30kV for sale or swap

[measures]

>I am the owner of what I think you call a " high pot". It is made by Danish
>firm Danbridge and goes fro 0  up to 30 kV. Basically it is, I think, a
>variable high impedance DC voltage source with an audio amplifier and a
>microammeter in series. As you turn up the voltage  you can hear every ion
>travelling across your test object and at the same time read the microampere
>current. If you increase voltage, you get a cracking noise that just before
>flash-over turns into a hissing sound. The flash-over should not harm your
>test object as the generatosr inherent resistance is high.
>
>Great for testing tubes, transformers, isolation and transmitters. However,
>I believe piezoelectric effects in ceramics may disturb the measurments?
>
I  have not observed this. 

>Weight is 12.5 kgs
>Dimensions 16 1/2W x 10 1/4H x 11 3/4D
>And is for sale or a swap deal?
>
>This instrument must be similar to yours Rich?
>
It is similar to my largest high-pot, except mine has no speaker.  I use 
a 15mm plastic tube to listen for corona.  . 
>
>
>
>>FrĀn: measures <2@vc.net>
>>Till: "Martin Ellis" <jmellis@ihug.co.nz>, "amps" <amps@contesting.com>
>>Ÿmne: Re: [AMPS] 2 x 3-500z amplifiers
>>Datum: mĀn 20 mar 2000 07.21
>>
>
>>
>>>
>>>Good morning,
>>>While activity is quiet on the reflector, I would like to raise
>>>a question about the TL922 amplifier:
>>>
>>>How can we assess the performance of individual tubes in a TL922?
>>
>>The most accurate way is to high-pot. the grid/fil.   Normal withstanding 
>>potential @2uA is 8 to 9 kV.  With a withstanding potential of under 5kV, 
>>the filament/grid may short when the tube is very hot.  The second most 
>>accurate way is to measure the grid/fil. C with a digital C meter.  
>>Anything over 10pF indicates that the filament grid clearance is 
>>abnormal.  
>>
>>>For example, after a major event is one tube faulty or do we need to
>>>replace both tubes?
>>
>>Only tubes with low withstanding potential need to be replaced.  922s 
>>typically short one tube per ''main event''. .  
>>
>>>Or if output is slowly going down, is one tube carrying the work load,
>>>or are both tubes getting "soft".
>>>
>>no info on such
>>
>>>
>>>It does not help to view the anode color, as one tube seems
>>>to get more cooling air than the other. 
>>
>>I measured the temp of the filament pins during operation.  The 922 
>>cooling is Way better than it looks.  The baffle with holes appears to be 
>>the key.  
>>
>>>As the filaments are in series, you cannot pull one tube,and all
>>>metering is of course for both tubes.  Is it permitted to lift
>>>one plate cap and operate the amp?
>>
>>No
>>>
>>cheers, Martin
>>
>>-  Rich..., 805.386.3734, www.vcnet.com/measures.  
>>end
>>
>>
>>--
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>>
>>
>


-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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