Typically to protect contacts from inductive kickbacks in AC, a snubber
network is used. As an alternative, can a MOV provide a reliable function
for the same purpose, i. e. will the MOV survive repeated strikes even if
chosen properly from the energy absorption viewpoint?
MOV's degrade with repeated surge currents (since it has to act like a
short circuit when it fires, localizied heat build up within the MOV
will eventually cause the whole MOV to fail).
I had better luck with gas tubes when we turned on large inductors
on/off and resulting L di/dt caused several hundred volt surges on
48VDC rail which would kill components left & right. Gas tube can
light up millions of times (it is also a great visual indicator to let
you know if it is still working or not)
without failing. I built an automated tester which would cause an
inductive surge every minute & the test ran 24 hours per day, and even
on weekends (so om one year, we created 24 hours x 60 minutes x 200
days of operation = 288,000 times). Even after 3 years (nearly 1
milliion firings), the gas tube held up just fine - it was awesome !!!