Using a solid state relay as a main stop relay

[garagefela]

Hi all,
As the heading states I would like to use a solid state relay activated by an e stop to stop main AC power coming into my power supply.

The relays will be adequately heat sinked so at least that part is in order.

I have several 25 amp relays kicking around and would prefer to use one of these over the mechanical type as I don't have any on hand.

Is there any reason why I should not do it this way??


Cheers M

[Al_The_Man]

You can if you wish, but many jurisdictions do not allow SSR for the E-stop string.
In fact now safety relays are becoming the norm.
If it is for your own use, there is nothing to stop you.
If this were a commercial machine, it most likely would not fly.
Al.
(ex-pom)

[garagefela]

Originally Posted by Al_The_Man Al. (ex-pom)

Thanks Al for that, yes it is just for home use only not commercial sale.

Happy to go this way just wanted to check to see what could go wrong.

Biggest one I can think of is if the SSR gets too hot they can stuff up and not "let go" when control power is removed but as I will place them on a big heat sink this wont be a problem.


Cheers M

[Al_The_Man]

The other down side on using an SSR for me is that I generally use a E-stop relay to cut off more than one source of power and maybe disable any drives at the same time, so I tend to use multi-contact control relay or contactor.
Al.

[garagefela]

Originally Posted by Al_The_Man The other down side on using an SSR for me is that I generally use a E-stop relay to cut off more than one source of power and maybe disable any drives at the same time, so I tend to use multi-contact control relay or contactor. Al.

Dammit, last night I was thinking about this very thing. I was just going to drop out the AC to the power supply and then I realised that I would also like to disable the drives, bugger it, I just knew I would not be able to use my relays.
Suppose I could just use two relays in the stop circuit but that's just a fleeting thought. You never know, maybe either could fail. Better with a single unit.

Stuff it Al, you have convinced my, I will go a huntin for the correct stop relay.

Plenty around when you start searching.

Cheers M