Why does the overload relay trip in a fridge compressor?

Overload Relay trips in refrigerator compressors are usually done to protect the compressor from damage. The function of the overload relay is to cut off the power supply when the current is too large to prevent overheating or damage to the compressor. Here are some common causes of overload relay trip:

Overload

• Difficulty in starting: If the compressor experiences difficulty in starting, it may cause excessive instantaneous current, which can trigger the overload relay.

• Continuous high load: If the compression is operated under high load for a long time, it will also cause the current to increase, exceeding the safety range set by the relay.

Electrical fault

• Short circuit: If there is a short circuit in the compressor or the related circuit, the current will increase abnormally, and the overload relay will trip.

• Grounding fault: If the circuit is poorly grounded, it may also cause current instability, resulting in relay operation.

Excessive temperature

• Poor heat dissipation: If poor ventilation around the compressor or a blocked radiator causes the compressor temperature to be too high, the overload relay may trip to protect the compressor.

• Refrigerant problem: Insufficient or too much refrigerant will affect the normal operation of the compressor, resulting in overheating or excessive current.

Mechanical failure

• Compressor stuck: If the internal parts of the compressor are stuck or seriously worn, it will cause difficulty in starting or excessive current during operation.

• Piston stuck: The piston stuck in the cylinder will also cause the compressor to not work properly.

Control circuit problem

• Relay failure: The relay itself may fail, resulting in misoperation.

• Poor contact: Poor contact between the compressor and other circuit connections may also cause overload protection.

Solution

When the overload relay tripping, should first cut off the power, and then investigate the specific cause. You can check by following these steps:

Inspection compressor

• Confirm whether the compressor can rotate freely to eliminate mechanical stuck problems.

• Check whether the compressor is overheated, clean the dust and debris around the compressor, and ensure good ventilation conditions.

Inspection circuit

• Use a multimeter to check whether the circuit is short or open.

• Check whether the power supply voltage is stable and eliminate the impact of voltage fluctuations on the compressor.

Check refrigeration system

• Check whether the refrigerant is sufficient, and eliminate leakage or excessive refrigerant.

• Check that the evaporator and condenser are clean to ensure good heat exchange efficiency.

Check relay

Check whether the relay is working properly and replace it with a new relay if necessary.If the problem cannot be solved after the above inspection, it is recommended to contact professional maintenance personnel for diagnosis and repair to avoid greater losses due to incorrect operation.