Data for ELEC-TROL 1980's solid state relays wanted

[adinsen]

A frend of mine cleaned up his workshop and gave me some stuff including these four ELEC-TROL solid state relays. Two are marked type PEZ-2D00 and two PEZ-2D04.

They are date coded 8106 and 8110 so they are pretty old, but unused.

It says "input 3-18VDC" and output 240 VAC, but nothing about any current, power rating or insulation. Googling ELEC-TROL solid state relays shows up nothing.

He bought them for a hobby project in the early 80's while he was working for NASA in Huntsville. He later returned to Denmark, where he now lives near me.

I did some simple measurements on one of them: The input side draws 1.5mA at 3V. Testing the output side with a 12V DC supply doesn't show any connection depemding on the input. Ohming the output pins show a 1M resistance between them. They are obviously not designed to switch low voltages and uA currents 

Judging by the size of them, they can probably switch a lot of current 

I hope someone might recognise them or could point me to documentation.

[edavid]

Based on the model numbers, my guess is that these are 2A SSRs with zero crossing triac output.  If that's correct, they won't work with a DC load.  Try connecting an AC powered incandescent bulb or power resistor to the output.

[adinsen]

Of course a triac circuit makes sense. 2A max rating seems very low. The PEZ-2D04 has a mounting bracket which I assume would double as cooling. A triac driving 2A will not get warm. The bracking is 2 1/4" (57mm) wide over the cooling tabs.

Thanks for the suggestion. I'll do some testing with it connected to the mains once I've made a safe setup for that

[edavid]

Thanks for the suggestion. I'll do some testing with it connected to the mains once I've made a safe setup for that

If you have a transformer, you can test it at a lower AC voltage.

[Zoli]

Of course a triac circuit makes sense. 2A max rating seems very low. The PEZ-2D04 has a mounting bracket which I assume would double as cooling. A triac driving 2A will not get warm. The bracking is 2 1/4" (57mm) wide over the cooling tabs.

Thanks for the suggestion. I'll do some testing with it connected to the mains once I've made a safe setup for that

Considering the year(1981; 8106, 8110 date codes), I think 2A triac make sense.

[LaserSteve]

I used to be chief revision/design tech for a company that made legacy SSRs. Odds are that is a  2A or 4A triac. Expect high leakage currents from the legacy protective devices, in other words your modern low current LED lighting loads may or may not go full off,  or you may feel a tingle if you touch  the circuit, assuming its off.  (Not recommended)

Steve

[adinsen]

Thanks all for your hints. Seems I've opened a can of "history of SSR's" here - interesting stuff 

I've done measurements with 23VAC from a transformer and a 250 Ohm load transistor. AC side is 50 Hz and the swiching is running 9 Hz. The first scope trace shows that the relay clearly does not have any zero detection, but otherwise works fine in this configuration. 

I used to be chief revision/design tech for a company that made legacy SSRs. Odds are that is a  2A or 4A triac. Expect high leakage currents from the legacy protective devices, in other words your modern low current LED lighting loads may or may not go full off,  or you may feel a tingle if you touch  the circuit, assuming its off.  (Not recommended)

Thanks for sharing, Steve! Inspired by your input I did another measurement, this time with a 12 kOhm resistor as load.
The second trace shows this. Clearly the relay works, but now we can see the leakage. I estimate the leakage current to be in the order of about 1 mA, if I read the trace correctly.

This makes the relays of limited use in a modern installation, but maybe I'll find use for them one day.

Thanks again all!

/Anders