William Sommerwerck wrote:
Uh... In the MOV?

I thought the MOV conducted above its breakdown voltage (generally around
300V), and the energy in the section of the AC waveform above that voltage
heated up the MOV.

Am I missing something?

In your typical plug in suppressor mounted next to the computer
for example. The job of the MOV is to clamp the maximum voltage
across the "protected" outlets. That it does this fairly quickly
is what hopefully protect the equipment, while at the same time
drawing enough current through the house wiring to either pop
the fuse or circuit breaker at the suppressor or back at the
service panel.

What the plug-in suppressors rely on is the impedance (generally
inductive) in the house wiring to limit the rise time of the
surge until the circuit breaker (or fusable parts) have time to
react by opening up.

The term joules can be described as Watt Seconds. And the ability
to deal with it is based on the fault (or surge) being over, or
the circuit breakers upstream open before the device self
destructs.

Whole house protectors work the same way in that they shunt the
current to ground safely before it has a chance to cause a
destructive rise to the rest of the house wiring.

Jeff



--
“Egotism is the anesthetic that dulls the pain of stupidity.”
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