Refrigerator relay pinout

Please, I need help on this. Have you ever seen a relay like this? Who can tell me the pinout for this???

Thanks Edu

The vendor you bought it from should be able to provide the pinout. As an alternative, you could probably use a multimeter to determine it.

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Edu ha escrito:

You are completely wrong. The white box IS the relay, and the black circular piece is the overload protector. You have to connect one of the two incoming wires to the remaining terminal of the overload (the black circular piece), and the remaining wire to the relay, which is the white box. The relay must be plugged in the compressor. The compressor has three pins and the RELAY (remember, the white box) should have three holes to plug it directly to the compressor.

One the 4 external contacts of the relay should be marked as common. That=B4s the one you will use to connect the remaining power wire. The other three contacts are provided in case you need to use a run capacitor, a start capacitor or both. If your compressor doesn=B4t need a cap, you just leave these contacts unused. If the common terminal isn=B4t marked, or the relay kit didn=B4t came with an electrical schematic, you should determine which one is common with a DMM.

Again: the relay is the white box, and the circular black piece is the overload protector.

If all this sounds like japanese to you, or you don=B4t know how to use a DMM, look for a refrigeration technician.

The other pins of the relay are provided to connect an startup capacitor, a run cap, or both, in case the compressor needs them.

Hi, thanks for the reply!

I'm not completly sure the relay is the white box. I disassembled it and there was only a ceramic disc, what I assume to be an overload protection. There are only two real contacts inside, one at each side of the ceramic disc. But each contact goes out by two pins each. So, I have 4 pins, 2 of them wired to one side of the disc, and the other 2 wired to the other side of the disc.

The black box is sealed. Pin 1 is wired to, but not connected to, an empty hole in the white box, as expecting to be jumpered to one of the

4 pins in it. Pin 2 and 3 are ready to connect to "something", but pin 3 is different, smaller than the other.

I have electronics and electric knowledge. I have tested both, and I get almost 0-ohm between every pair of pins in the black box, and 0 ohm between both sides of the white box.

Any idea??? Im completly lost!

Regards! Eduardo

lsmartino ha escrito:

Edu ha escrito:

This is because the "relay" is a PTC, used to provide a momentary pulse to the starting windings of the compressor. As soon the PTC "relay" heats, it resistance increases and the voltage applied to the starting winding is vastly reduced. It operates under the same concept as a PTC for the degaussing coil inside a TV. The PTC relay is a substitute for the electromagnetical relay in modern compressors.

Google for "Tecumseh" and have a look at the starting circuits of some compressors. That should give you an idea about what to do with the starting kit you have.

And again, the black box IS an overload.

Ok, thanks for your time. Now I think I understand everything! So, I have to wire the white box (relay) between run and start, and apply 220v to common and run, placing in series the overload protection (black box).

As the overload protection has 3 pins, I assume pins 1 & 2 are the "in/out" pins, and the 3rd pin, which is a thinner faston, is for some add-on line start or run capacitor. The original relay didn't have any capacitor, so maybe I can left pin 3 unconnected.

Am I right??? I can see the light at the end...:-)

Thanks a lot!

Regards. Eduardo.

lsmartino ha escrito:

Edu ha escrito:

The overload protection has only TWO contacts. The center screw is for adjusting the overload protector at factory, its NOT a connection pin to anything.

Remember that the PTC relay should be plugged directly to the compressor. In one of the sides of the relay, there should be three holes. Align these holes with the three compressor pins, and plug the PTC relay there.

This is a schematic from a refrigeration compressor. In the page two you will find a wiring diagram:

Well, actually the overload has 3 real pins, none of them is a screw, but it is true that the one numbered "3" is a half-width faston, while

1 & 2 are normal fastons.

The relay has 2 real faston plugs at one side (both to the same side of the PTC), and at the other side I think there are 4 small holes which might plug directly to 2 pins from the compressor (start/run). Maybe the spare wire which comes from the overlad to an empty hole in the relay is intended to make it match the position of the "common pin" in the compressor (see photo I attached, altough it is right in the opposite side, at the end of the black wire).

This weekend I will to to make the last compressor I have alive run... I hope everything works! Your should have seen the wiring I made at my first attempt ! It has changed a lot since your help ..!! :-)

Thanks a lot for your time!

Best regards! Eduardo

lsmartino ha escrito:

Edu ha escrito:

This sounds right. That way the overload will get connected to the common pin of the compressor, thus protecting both the start and run windings.

Good luck then!

Hi again!

Could you believe the relay fitted directly into my compressor! The opposite side from the side seen in the picture I took, has both start/run plugs in the neccessary size, and the spare wire coming into a hole from the overload protector was, as we supposed, directly plugged in the common pin. I was making difficult the easy things.

Now the compressor works perfectly. The only thing I have noticed is the stop time I must allow between stopping and starting again. I have read somewhere about the time the PTC needs to cool again. I don't think it would be a problem (the compressor is not intended for a fridge, I will boild an air compressor with a fire extinguisher as a deposit...

Thanks for opening my eyes, and best regards! Eduardo

lsmartino ha escrito:

Edu ha escrito:

I believe you because that was exactly what I tried to tell you in the previous posts. Maybe we could communicate better if we used Spanish in the the first place. :-)

Exactly, the PTC needs to cool down in order to work again. Is exactly the same thing which happens in a TV with the degauss thermistor.

I=B4m glad to see that you could complete your project. Next time you have to replace a realya like that in a freezer, you will know what to do.

Are you Spanish too??? :-)

Well, my complete project is an air compressor. I still have to find some other components and make practise in copper soldering... The person who gave me the compressor for free from an old refrigerator, has just asked me about repairing his kitchen refrigerator, which has just stopped cooling. Now I have more information about it. Some weeks ago I though the compressor was a three-phase motor started with 1 phase and a starter capacitor...:-) And many other things I have learned surfing the web these days in search for more info (about nofrosts systems, for example).

Thanks again, and best regards! Eduardo