Re: NST insulator

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips" <evp-at-pacbell-dot-net> 

"Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi,

Usually the insulator protrudes well into the case so it is not easy
just
to remove or replace.  The insulators are far over designed and really
made
to work with frost and such on them.  So pretty significant damage may
not
hurt the function all all.  Personally, I would just epoxy it and not
worry
much about it.

I hear a lot about insulator damage from E-bay and other shipped NSTs.
The
insulators have to be protected very well so even if the box is dropped
on
the side with the insulator pointing toward the concrete it will be
protected.  You can't pack them "too" well...

Cheers,

          Terry"

	I'll add something to that.  Perhaps 20 years ago I was coming home
from work and, on driving up a freeway onramp noticed what appeared to
be an NST lying in the ice plant beside the road.  I was able to detour
and get back on that ramp and found 4 NST's which had obviously slid off
the bed of a truck, bounced their way across the pavement shedding bits
of insulators, and ending up in the weeds.  All four (1 9 kV 60 ma and 3
12 kV, 60 ma) worked fine with no repairs.  In all cases the external
part of the insulator was shattered and in a couple the screws were
broken off short, but the leads were still centered in the hole.  I
eventually took the 9 kV transformer apart and replaced the worst
insulator with a piece of fiberglass rod, but it really wasn't
necessary.

Ed