What sort of current can your hi potter provide in an arc? Depending on
the energy it dumps, you might be careful when raising voltage above the
ratings of parts. I would not risk running capacitors or wiring,
rectifiers, above their rating. If they are vacuum capacitors you can
get away with higher. For tubes, you should be able to test them above
rating. Most of the ratings are for circuit operation, and in AM it is
much lower than it is for FM/CW, due to the modulation peaks. But high
potting a tube out of the amplifier circuit, should allow running them a
few kV above the datasheet operating maximums noted above. I high pot a
tube that runs at 15 kV, at 20-25 kV typically when new. With a high
potter than can only run a few mA, the risk of damage due to an internal
arc is low, if the high potter can shut off quickly. When I hi pot a
tube and it does breakdown internally, it just tics the current meter
and clicks off the high potter. This is benign for tubes, unless you
have a nasty flash arc over the outside of the tube in air and the high
potter says on.
73
John
K5PRO
Date: Fri, 12 Feb 2021 17:39:46 -0500
From: Steve Bookout<steve@nr4m.com>
To:Amps@contesting.com
Subject: [Amps] Hi-pot testing
Hello all,
Several months ago, I had a problem with a 40 year old HB amp for 160.?
Just sitting there, it started making an arcing noise (sort of) and
showed plate current jumping around.
Now, I'm finally looking into it.? I'm using a HB hi-pot tester and am
testing pieces and parts up to their voltage rating.? FYI, the plate
voltage is 4 KV and most things are rated much higher.?? I was checking
things out at 5 to 6 KV with very minimal current showing.? Happy with
that.
Question:? Someone once told me that new Eimac tubes were tested at
twice their rated voltage.? Ok, fine.? What about capacitors????
So, what should it test if it were brand new?
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|