16 May
2012
16 May
'12
9:32 a.m.
On Tue, May 15, 2012 at 3:41 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
We ran ours around 900V-2200V, but, yes, you want to test around
operational voltage to look for leaks. We found them - not usually by
brushing up against the cables, fortunately, but because bad cables
tripped the source crowbars (they would only permit a few mA before
shutting down a channel to prevent damage). I believe our issues were
more with a damaged internal conductor than the external jacket -
caused often by aggressive ty-wrap installation.
Right.
I've used a megger to test HV lines powering photomultiplier tubes.
I am suprised they;'re a high enough voltage for that, I seem to remeber
using about 3.5kV to 5kV to power a PM tube, so you'd want ot megger it
at at least that (HV leaks are nsty thigns that tend not to appear until
you get close to the working votlage. This is, of ocurse, Murphy's Law...) Never used one
with classic computer gear (yet).
Well, obviously you dont; use them anywhwere near the logic (unless you
work on vlaved machines :-)). But I do chekc the isulatuion fo mains
transfiormers, fans, etc with one. It's better to find the leak.breakdown
that way than by having the mains ps thotuh you (or worse, the logic boards!)
I've not had issues in that area, but it's always good to know the
right tool for the job.
-ethan