[Test-Equipment] Another boat anchor - Del Electric High voltage supply?

[Carl]

----- Original Message ----- 
From: "rbethman" <rbethman at comcast.net>
To: "Discussion of Electronic Test Equipment" 
<test-equipment at mailman.qth.net>
Cc: "KM1H Carl" <km1h at jeremy.mv.com>
Sent: Friday, November 05, 2010 12:23 PM
Subject: Re: [Test-Equipment] Another boat anchor - Del Electric High 
voltage supply?


>I do understand high potential testing.

I wonder if you do understand other forms of HV non destructive testing

>
> When I "look" at the voltage range - and "see" 40 to 50KV on the metering, 
> even testing to 4 times the plate voltage, would mean that one is using 
> around 5KV in the final.
>
> The ONLY place I see that used would be a 3-1000 or 4-1000A final in an 
> amplifier.


Those are OK for glass tubes. Others use tubes with handles in those 
converted BCB rigs.

The CBers go even higher and are rather fanatical about hi potting those 
20-40KW dissipation tubes they buy


>
> I'm NOT going into the 40KV to 50KV range in my shack.  That sort of 
> testing requires an appropriate lab, equipped with a "cage" to retain 
> pieces and parts.


Not necessary at least to 40KV otherwise you couldnt use an older TV.  We 
are not talking power here, just voltage at very low current capability from 
the transformer that is further severely current limited. Leakage in a tube 
is measured in microamps. The whole setup fits on a table with the control 
section isolated from the HV with Plexiglass or Lexan so you can also see 
what is going on if necessary. If you get too close your hair will react. 
The transformer can be a 13-14KV neon sign transformer with a doubler. The 
low value filter caps take up most of the room.


>
> I "can" understand 10KV to 16KV.  The old color TVs did indeed go upward 
> to about 30KV.  You had to bypass a fair bit of safety to get near it.
>
> Bob - N0DGN

Here is some good reading for the home brewer that has been built by many.

Carl
KM1H





>
> On 11/5/2010 12:03 PM, Carl wrote:
>> For AM you want to test to at least 4X the plate voltage; this makes
>> 10-16KV+  rather a standard part of the test.
>>
>> Several megohms as a current limiter protects from tube damage as the
>> voltage is slowy increased while watching leakage current.
>>
>> Carl
>> KM1H
>