Compressor Motor Overload
refrigeration
Description
A low-suction or refrigeration alarm occurred with current below 5.5 amps, or restart current did not rise above 1 amp, and the engine or refrigeration system shuts down with an alarm.
Activation Conditions
If alarm 00022 Low Suction Superheat, 00027 High Suction Pressure and/or 00028 Check Refrigeration System was triggered with current below 5.5 amps. This alarm will also trigger on restart from alarm 00022, 00027 and/or 00028 if compressor current does not rise above 1 amp, and alarm 00013 High Discharge Pressure is not active.
Unit Behavior
Engine: Engine and unit shutdown and alarm. Electric: Refrigeration system shutdown and alarm with PSCON still energized. NOTE The compressor motor is fitted with an internal line break that may have caused this alarm. The line break is an auto reset device. Additional time may be required to reduce winding temperature to the reset temperature of this device.
Reset Conditions
Auto reset after 30 minutes alarm may be manually reset via keypad or by turning the unit off, then back on again.
Corrective Actions
1. Check for Alarms 00022, 00027 and/or 00028 (Check Download) - These alarms will always cause 00075 to activate. Review steps for triggered alarms and correct if necessary. 2. Check Compressor Power Supply - Start unit and check voltage. Normal low speed voltage at contactor should be greater than 360 and less than 460V. Check current on each phase. Current must be greater than 0 and less than 18 amps. (Compressor is operating.) If voltage is present and current is 0, motor is overheated. Wait for compressor to cool for 30 minutes and check again. If voltage and current are not present at load side of contact check compressor contactor operation. 3. Check Compressor Motor Contactor - Check condition and wiring Repair/replace as required. 4. Check Airflow Through Radiator / Condenser Coil a. Inspect condenser / radiator fins. Fins must be straight. 90% or more of the coil surface must be undamaged. No “dead” air spaces. Coil must be clean (refer to Section 8.5.11). b. Check condenser airflow. Even airflow through the entire coil. No “dead” spots. c. Check condenser fan rotation / operation. Fans should operate correctly. Air drawn in through the grill, and directed into the engine compartment. 5. Check System for Non-Condensables, Low Charge - Check refrigeration system for noncondensable gas(es). No non-condensable gas(es) may be present. Refer to Section 8.6.2. 6. Perform Pretrip, Verify SMV and ECXV Functionality Clear Active Alarm list, then run Pretrip and check for any new alarms. Any active alarms must be corrected and cleared before proceeding. 7. Verify Accuracy of AC Current Sensor a. Put microprocessor in PC Mode. Refer to Section 5.3.2. Must have 0 AC1 Amps and 0 AC2 Amps in Unit Data. b. Use a clamp on ammeter to measure current draw of all three legs of the T side of GENCON. Meter reading should be the same as Unit Data: Compare meter reading to Unit Data in PC Mode. Compare meter reading to Unit Data with unit under load. 8. Check Compressor - Check compressor for excessive vibration or noise. Replace compressor. Refer to Section 8.7