[Amps] MOV's

[jljarvis]

Careful, here.....MOV's shift characteristics with dosage, and
may only be good for a few shots, depending on the charge it
has to absorb, per shot.

<snip>
>a MOV across the contacts cures the  problem better than a vacuum-
>>relay since the reverse EMF still needs to be suppressed to prevent
>>damage elsewhere.
>
>The problem is that because it's DC, even with no inductive load,

€  If wires are used to connect a (pretend) purely resistive load, the
load always looks iinductive.  And when the circuit opens, a reverse EMF
at the opening contacts is guaranteed.  Good engineering practice is to
suppress reverse EMFs with a MOV or bi-lateral Si transient suppressor
diode.
<snip>

I did some work with MOV transient suppressors in a previous lifetime.
If you zap them in opposite directions more or less equally, they can
last a while.  Zap them in one direction, like reverse EMF, and they
will become increasingly less useful.

Jim N2EA

PS:  TWA's (retired) senior 747 check pilot at the time of the 'center fuel tank'
explosion, still believes it was friendly fire that downed the aircraft.