HV Testing (was:Re: Newbie's got a dead 386)

From: Daniel T. Burrows <dburrows_at_netpath.net>
Date: Thu Nov 19 09:03:59 1998

>> Another one - How do you test supplies and various heater controls that
>have
>> to float at 8Kv? I.E.: their common point is at 8Kv. Especially when
>they
>> are intermittent and you can't tell without the HT on exactly when it is
>> acting up. VERY carefully float your meter at kV and be very sure you
>don't
>> touch the meter and don't do like I did and get to near the leads while
>> operating the instrument while waiting for the intermittent to act up.
>An
>> 8Kv _at_ 5ma with 1ppm stability supply burns holes on the way in and out.
>In
>> the arm and out the finger.
>
>I'd recommend:
>
>1. Get one of those rubber holsters for the meter and allow only the
>holster to touch the equipment.
>
>2. Make some test leads out of EHT wire. The sort of stuff that's used
>for the anodes of CRTs and things. Maplin used to sell it (haven't checked
>recently), rated at 25 kV, and I'm sure other suppliers do too.
>
>3. Failing no. 2, car engine HT leads may be useable, but most of them are
>quite rsistive, so check the calibration!


I agree but that adds weight and bulk to an already overstuffed and heavy
tool / parts case that I will not check through airline baggage. It is
something that I have to do only a couple times a year so I realize I am
taking chances and after the bite of 8Kv I tend to be even more careful. I
have some 40KV rated test lead which would work but it is bulky for use on
the road.
Keep in mind that I used to be in 2 to 4 cities a week. 99% of the time
with airline flights between each city. Weight and bulk is a BIG
consideration then.

The most important thing I was trying to point out with the first item in
that post is NEVER assume the meter is correct. It will bite you.
Dan
Received on Thu Nov 19 1998 - 09:03:59 GMT