Testing an SSR - Can you?

[KEG99]

If an SSR fails closed, would a good SSR test out open, i.e., would you read no resistance and that means it is still good?

 

[atoughram]

If you read zero resistance, with it out of the circuit, it's bad. If you read infinite or very high resistance with it out of the circuit it could still be good. If it failed closed, you would read very little resistance across the outputs with the SSR out of the circuit.

 

[KEG99]

Thanks. And since by design, an SSR will fail in the closed position, this should always be the case.

 

[Indian_villager]

Could you wire an LED in parallel with the element and check the pulsing of the led with the pulsing of the output light on the PID itself?

 

[atoughram]

Thanks. And since by design, an SSR will fail in the closed position, this should always be the case.

I'm not sure that they always fail closed. They could fail open too - maybe not likely in the way we used them, but possible.

 

[atoughram]

Could you wire an LED in parallel with the element and check the pulsing of the led with the pulsing of the output light on the PID itself?

Yes - But with the element un-plugged, the LED indicator on the output will stay on constantly because of leakage current.

 

[michaeltrego]

Yes - But with the element un-plugged, the LED indicator on the output will stay on constantly because of leakage current.

Assuming the LED is 240V, the amount of leakage wouldn't be sufficient to light the bulb, no?

 

[Brumateur]

Leaking voltage is 240V so it will light ann LED or neon lamp. But current is vrey limited . So if you connect something which require 1Watt of power or more voltage drops almosf to 0.

 

[processhead]

A good way to test these is to wire them with 120 volt AC supply and connect them to a load like a table lamp or ordinary incandescent light bulb.

An incandescent light bulb is a large enough load that normal leakage current won't light it.

You should be able to switch a normally operating SSR with your PID in manual mode, or even a 9 volt battery wired as a temporary control voltage source.

 

[wstev]

I've found on my ssr's, if I connect hot to pin1 and element side to pin 2 then my led indicators do not come on when no element is connected. As soon as I reverse the two, my element led turned on about to half it's brightness.



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