Destruction of solid state relays

[vinnygalbo]

My luck sucks with solid state relays. And since I am not a great believer in luck, I'm thinking I do something that kills them. I can't imagine what though.

My streak of bad luck started with releco relays like this one.

https://www.clrwtr.com/Products/CSS-N13X-DC5-48V

we were using 48V versions. Originally these were the type that switched with 120V, but later we used the kind switched with 24V.

We also had issue with high amp relays from omega that also switched 120V AC from a 24VDC coil.

http://www.omega.com/pptst/SSRL2

Since the failure rate is high, we are planning to switch again.

So: What can cause solid state relays to fail? and way more importantly, what inexpensive way is there to detect and subdue a failure, because each and every failure was a closed circuit! So heaters go ON when a relay fails. That is bad news!

[OldSchoolProgrammer]

You didn't say what sort of load the SSRs are supplying. An inductive load such as a motor or the coil of an electromechanical relay generates a voltage kick-back when power is removed from it, and the kick-back voltage can be many times the supplied AC voltage. A resistor and capacitor in series (a snubber network) placed across the output of the SSR can absorb the kick-back voltage, but you'd have to know the electrical characteristics of the load before choosing the components for the snubber network.

[mactec54]

My luck sucks with solid state relays. And since I am not a great believer in luck, I'm thinking I do something that kills them. I can't imagine what though.

My streak of bad luck started with releco relays like this one.

https://www.clrwtr.com/Products/CSS-N13X-DC5-48V

we were using 48V versions. Originally these were the type that switched with 120V, but later we used the kind switched with 24V.

We also had issue with high amp relays from omega that also switched 120V AC from a 24VDC coil.
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Since the failure rate is high, we are planning to switch again.

So: What can cause solid state relays to fail? and way more importantly, what inexpensive way is there to detect and subdue a failure, because each and every failure was a closed circuit! So heaters go ON when a relay fails. That is bad news!

They most likely failed because of not using a snubber, some SSR have a snubber-built in. always look at the spec's or add a snubber if needed or you will have failures