Inductive load and SSR: snubber, zero-crossing, random-fire..

Hello :)

Recently I have read a lot (but maybe not enough) about solid state relays. I have read mixed and confusing answers about using SSR for controlling inductive loads.

In one place I read that a SSR with random-fire switching MUST be used. Somewhere else, I read: zero-crossing switching will also work fine. In another website, I read: if the SSR have a snubber circuit on the output, it will also work fine...

So I'm confused about what kind of SSR I could use. Can you enlighten me?

My conclusion from all I've read, is:

  • snubber + random-fire = ideal
  • snubber + zero-crossing = good enough
  • no snubber = bad.

Can you confirm this?

Edit: I also read that it's a good idea to add a metal oxyde varistor across the output terminals, with a value around voltage*1.8, to protect relay from spikes.

Thanks ;)