Systems and/or methods for controlling a compressor and/or a fan motor

A vapor compression refrigeration system, comprising:

• a compressor configured to suction refrigerant at a low pressure and temperature from a suction return, compress the refrigerant, and output refrigerant at a higher pressure and temperature;
• a condenser configured to cool refrigerant received from the compressor as the refrigerant passes though coils in the condenser;
• an expansion device configured to reduce the pressure of the refrigerant received from the condenser;
• an evaporator configured to allow the refrigerant received from the expansion device to absorb heat surrounding the evaporator;
• an evaporator fan motor configured to provide air flow across coils in the condenser;
• a first sensor configured to measure a temperature of the evaporator fan motor windings;
• a second sensor configured to measures a temperature on an air supply coming from the evaporator;
• and
• a controller including circuitry coupled to the first sensor, the second sensor and the evaporator fan motor, the controller configured to:
• receive a first signal corresponding to the temperature of the evaporator fan motor windings from the first sensor;
• receive a second signal corresponding to the temperature on an air supply from the second sensor;
• control the evaporator fan motor to turn off based on the first signal indicating that the temperature of the evaporator fan motor windings is above a set point;
• and
• control the evaporator fan motor to increase operating speed based on the temperature on the air supply approaching the set point.

A method for controlling a vapor compression refrigeration system comprising:

• a compressor configured to suction refrigerant at a low pressure and temperature from a suction return, compress the refrigerant, and output refrigerant at a higher pressure and temperature;
• a condenser configured to cool refrigerant received from the compressor as the refrigerant passes though coils in the condenser;
• an expansion device configured to reduce the pressure of the refrigerant received from the condenser;
• an evaporator configured to allow the refrigerant received from the expansion device to absorb heat surrounding the evaporator;
• a first sensor configured to measure refrigerant discharge temperature between the compressor and the condenser;
• and a second sensor configured to measure refrigerant temperature on the suction return;
• the method comprising:
• receiving a first signal corresponding to the refrigerant discharge temperature from the first sensor;
• receiving a second signal corresponding to the refrigerant temperature on the suction return to the compressor from the second sensor;
• controlling the compressor to turn off based on the first signal;
• and
• controlling the compressor to reduce frequency speed of the compressor based on the second signal.

A method for controlling vapor compression refrigeration system comprising:

• a compressor configured to suction refrigerant at a low pressure and temperature from a suction return, compress the refrigerant, and output refrigerant at a higher pressure and temperature;
• a condenser configured to cool refrigerant received from the compressor as the refrigerant passes though coils in the condenser;
• an expansion device configured to reduce the pressure of the refrigerant received from the condenser;
• an evaporator configured to allow the refrigerant received from the expansion device to absorb heat surrounding the evaporator;
• an evaporator fan motor configured to provide air flow across coils in the condenser;
• a first sensor configured to measure a temperature of the evaporator fan motor windings;
• a second sensor configured to measures a temperature on an air supply coming from the evaporator;
• the method comprising:
• receiving a first signal corresponding to the temperature of the evaporator fan motor windings from the first sensor;
• receiving a second signal corresponding to the temperature on an air supply from the second sensor;
• controlling the evaporator fan motor to turn off based on the first signal indicating that the temperature of the evaporator fan motor windings is above a set point;
• and
• controlling the evaporator fan motor to increase operating speed based on the temperature on the air supply approaching the set point.