An instrument tech told me to use an mov. varistor. I try two types and they didnt work one allowed a little more out put voltage than the other but they didnt work. I dont know how to size them either.
Thnx for the advice
Yikes! Don't do that! (just ask Trace Adkins).
When a MOV conducts, it's a dead short to whatever you have the other lead connected to (pretty much it's always connected to ground). This will destroy your prox, and possibly take the entire control circuit with it.
And (this is the Trace Adkins part of the story) each time a MOV conducts, its breakdown voltage is lowered. Meaning that the next time it will conduct that much more, that much sooner.
And if you have the MOV "protected" by a circuit breaker that is much larger than the capacity of the MOV, then the MOV catches on fire.
The newer style of MOVs have what looks like a hunchback on them. This is a thermal fuse that will open the MOV up should it get too hot (but there goes your protection...).
This is better than catching the MOV on fire, but not by much (something else will likely catch on fire).
And it's unlikely that you are seeing much of a surge coming into the coil. The coil on the relay is going to take care of that. However, once the power is removed there is going to be a spike that can cause noise and/or accelerated contact wear. This is where a "snubber" comes in. This is probably what he meant:
http://www.bpesolutions.com/bpemanuals/Snubber.pdf
But it's not going to help you in your leakage problem (but you should always have snubbers for your AC relays and diodes for DC relays).
And as an aside, if you have a time critical operation then you want DC relays (no zero crossing delays), *but* you will want to add a resistor in series with the diode to get the relay to turn off as quickly as it can.
I've been told that you want to size your resistor to match the coil resistance.
https://www.physicsforums.com/threads/flyback-diode-on-solenoid-slows-solenoid-retract-time.747525/