Three pin refrigerator thermostats?

Davej <galt snipped-for-privacy@hotmail.com wrote

One terminal is the common. That is connected to one or other of the other two terminals depending on whether the temperature is above or below the set point.

Oh, so what would a refrigerator need to apply power to when it shuts off the compressor?

Davej <galt snipped-for-privacy@hotmail.com wrote

It doesn’t, its just the way thermostats are usually done.

You see the same thing with oven thermostats too.

Its more obviously useful with room thermostats.

Hmmm, I've just removed one from a dorm-sized fridge and there was a wire on every terminal.

Some thermostats do have an internal heater. That reduces the hysteresis in the thermostat. Bit counter intuitive why that approach works.

Now that you have it out, easy to use a multimeter to see how that one uses the terminals.

Not likely, I bet there is a wire connected to all three terminals. It may be part of a design so that the defrost heater is only powered when the compressor is off.

It's not useful there, of all places. I never had a thermostat that was more than a simple on/off switch for a home heating system. Some have two stages, but that's another story.