Dead SSR from old Environ 2 Strand Dimmer

[PeaceTech]

Recently a bank of 10 lights went out in our houselights. Unfortunately, come to find that the dimmers are Environ 2 Strand Electro Control dimmers from 1983. We were able to diagnose the problem down to a bad SSR but I have not been able to track down anyone with the proper amperage/voltage SSR. The specific part seems to be either obsolete or impossible to find. I am attaching a photo of the SSR and the dimmer tag for reference. Does anyone have any idea where I could find one of these?

 

[JD]

You may not be able to find an exact replacement, but an 80 amp SSR is a pretty generic device. There are many on the market. The Solid State Relay, or SSR, was not something designed for the lighting industry, we just adopted it because it allowed the dimmer design to be simplified by eliminating the opto-isolator and gate drive circuit.

There are two types of SSRs; "Zero Voltage Cross" units, and "Anytime" units. In dimmer systems, we use the "Anytime" units because we want to phase chop. (ZVC SSRs are designed to turn on at the beginning of the waveform irrelevant of when the input signal is applied.)

If a substitution is done, the voltage and current ratings should be the same or higher.
Needless to say, I am assuming you are qualified to do the repair. If not, then you should not be doing it.

Fun Facts:
What is inside a SSR?
The input terminals feed a resistor and an LED. The LED activates a photo triac, which is used to drive two back-to-back SCRs (or a Triac) with a couple of resistors thrown in for gate current limiting. All comes in a handy potted block, which makes them fun to use!

 

[headcrab]

H12D4890 Crydom Solid State Relays

 

[phenry]

That exact relay is not manufacured anymore, but we do have a replacement that is the same form and fit, but a higher amperage. The Strand part number is 2-377013-010. Any dealer or service center listed on our website will be able to get one for you. If you have any trouble locating one, let me know and I will help you out.

 

[JD]

H12D4890 Crydom Solid State Relays

Watch out. You need to end the part number with -10 or it will come in the Zero Voltage Cross version.
More on this PDF:
http://www.crydom.com/en/Products/Catalog/h_12.pdf

 

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[PeaceTech]

Thanks for all the replies!

H12D4890 Crydom Solid State Relays

My local theatrical supply company sent me this replacement SSR and it caused the control module to read "Over-temp". This caused the lights to only turn on in panic mode. I am going to attempt the Strand Part # listed above. Thanks again for the help!

 

[JD]

As I stated above, that part does not allow "anytime" turn on and will not work in a dimmer. The end of the part number should read -10 to work for your application. You need HD4890-10

As the HD4890 has an internal ZVCD, it will only work in the off and full on modes. As the SSR is ignoring the trigger, there is no output and thus the error.