Compressor PTC Start Relay. Restart time?

[oakleyjo]

Hi,

If I get a fridge compressor to start (by bypassing the thermostat) and then disconnect and reconnect the power to it, should it restart straight away, or does the PTC need to ‘recover’ for a short period because of the way it works?

What I see if the compressor starts and runs the first time. The next time it doesn’t start, there is noise from the run windings, and then there is a click from the overload protection. If I let everything settle for a while it starts up again ok.

Sorry if it’s a stupid question … but if you don’t ask the stupid questions you don’t learn 😉

Thanks,
Jon

[SAMURI]

Re: Compressor PTC Start Relay. Restart time?

If you try to restart a compressor too soon you run the risk of seizing the compressor.

The compressor will not restart straight away due to the pressure in the system and cuts out on the thermal overload until the pressure drops.

Bob

[madangler1]

Re: Compressor PTC Start Relay. Restart time?

Normal, the compressor needs the gas pressure to equalise both sides of it. When its been on and you shut it down and try to restart it straight away the high side pressure is to much for the compressor to handle and the motor stalls and the overload kicks in.

[oakleyjo]

Re: Compressor PTC Start Relay. Restart time?

Interesting. So it’s not the PTC that needs to recover, it’s the compressor itself. Is there a minimum amount of time that’s recommended between restarts to be confident the pressures have equalized?

[Author]

Posts