SSR acceptable for 32A AC load?

Discussion in 'General Electronics Chat' started by Crispin, Aug 19, 2011.

  1. Crispin

    Thread Starter Member

    Jul 4, 2011
    Hi Folks,

    I have two 11pin relays acting as change-over relay to change between inverter and grid as a 230V source for some of the mains rings in my house.
    The relays are a bit slow and cause some equipment to get upset on switching. I was wondering if SSR would help out.
    Some issues I am wondering about are:
    - Will the sine wave still be clean or will there be any choppiness to it that might annoy some equipment?
    - Will it only truly switch off as the voltage crosses zero? This would be catastrophic as I would have two, out of phase sine waves bumping into each other as the one is still on and the other has just turned on.
    - The interlock (electrical) safety between the two relays becomes software / additional hardware controlled now. (not loving that)
    My current solution is to get a few very small in-plug UPSs like this[​IMG] on the problem stuff which will soften the change over. It’s not the cleanest but serves a dual purpose so not totally against it. Just wondering if I can make it “cooler” with SSRs.

    Said change-over will happen very seldom as it is a fail-back for then the invertor batteries are empty.
    (see attached for basic – what I am talking about)