RE: MOVs, auto AC power disconnect fault ckt

["Dale Hall" <Dale.Hall-at-trw-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Herwig, Terry and All,
MOV posts spawned an idea:
to provide timely (say a few seconds) 
auto AC power cut off when MOV string begins heavy current conduction:

Consider implementing, in series with the Sec HV MOV string, 
a HV relay coil (Jennings, etc. 25kV rated, coil to contacts isolation >> 50kV)
or LED (w/protect network) using appropriate fiber optic for HV isolation
to remote detector,
   with appropriate RC for averaging to avoid nuisance trips,

to detect overcurrent fault condition and cause release of a latched
primary power relay.

-----

Herwig do you have vendor/URL/phone#/adr for those 4500A MOV's at 32 for $20 ??

Regards, Dale

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, July 20, 2000 7:13 AM
To: tesla-at-pupman-dot-com
Subject: Re: MOVs

Original poster: "Herwig Roscher" <herwig.roscher-at-gmx.de> 

Terry Fritz wrote to the list:

> The 2500 amp ones run for about 30 seconds into a pretty good overload

Terry,

So, using 4500 A ones in my system, I'm on the safe side :-)

> They run a little over a buck each.
For 32 pcs I've payed 20 bucks.

> With lots of transformers, the 6500 amp ones may give you a bit
> more time to turn it down before the MOVs are damaged.
My tranny deliveres 280 mA/12 kV and therefore I'd better react 
quickly. 

Thanks and bye. Herwig