"David" wrote in -
september.org:


Bull****. The Mov dissipates (Umov)*I*T, or
Total Energy=MOVvolts * Current * Seconds.
Or integrate over those values, if they vary in time.
The Mov voltage does NOT drop to zero, when conducting.

I never said it did.
the MOV voltage rating is the voltage when it changes
state and drops to a
low resistance to shunt the surge to GROUND.
Now,how low a resistance in the conducting state is
another matter.
that's dependent on the MOV design/ratings.


Where did you learn about electricity??????

USAF PME School,1971.

Of course some currents might be enough to blow the MOV,

yes,I said the MOV's dissipation would be
"minimal",....compared to the
total energy the MOV was passing to ground.
what energy the MOV dissipates can easily be enough to
blow it apart.
I've seen it happen many times.
But the MOV is not dissipating the total energy of the
surge with it's
suicide.

Jim Yanik
jyanik
at
localnet
dot com

A MOV is somewhat like two back-to-back Zener diodes. It is
a voltage clamp.

no,it's not. it does not "clamp" the voltage.

You do not pass energy to ground, you pass
current to ground just like you do with any load. The energy
is totally dissipated in the MOV.

David




totally wrong.
Wiki has a nice article on metal-oxide varistor,I suggest you read it.

--
Jim Yanik
jyanik
at
localnet
dot com