SSR or EMR
SSR or EMR
(OP)
We have a big Washer in our Heat Treat room. There is a 100amp relay or contactor that is turning on and off every minute. Yeah I know, but that's the way the machine came brand new. They also sent a replacement contactor because they said it would go out in 6 months. I am looking into a different setup. I replaced some other contactors with a mercury style that are still working on another machine that was cycling a lot also. The problem with an SSR is that if the SSR goes out they usually go out shorted and the contactor is running heaters, which would not be good. Anyone have a different idea?





RE: SSR or EMR
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: SSR or EMR
Deetz, use an SSR for temperature control in series with a contactor for over temperature control. Can you still even buy mercury contactors any longer? Environmental regulators have been very aggressive in removing mercury from commerce wherever possible.
RE: SSR or EMR
RE: SSR or EMR
RE: SSR or EMR
Ditch the mercury contactor.
Reinstall the original contactor.
CORRECTLY install a Solid State Relay rated at 100 or 120A.
Purchase and install a second device called a "process alarm" used as an over temperature monitor that only controls the original contactor, dropping it during an over temperature event.
Here's some examples, some of which are 3phase and some are single phase and would, of course, require three.
http://www.thyristorscr.com/product/three-phase-solid-state-relays_id16.html
Digikey SSR search
Keith Cress
kcress - http://www.flaminsystems.com
RE: SSR or EMR
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: SSR or EMR
Then on top of that they get a revenue stream from all the replacement contactors they sell to their customers over the years of use..
RE: SSR or EMR
Well, almost.
RE: SSR or EMR
A limit controller needs to be manually reset after it trips (on high temp); its output drives the contactor which interlocks the energy going to the heater.