Specifications

10 Catalog WSC/WDC-4
Why a Compressor Motor Failure Will Not Contaminate the Common
Refrigerant Circuit
The compressor motor is isolated from the main refrigerant flow circuit so that any contaminants
generated by a motor failure will not pass into the main refrigerant circuit. Moisture, acid and/or
carbon particles will be automatically trapped within the compressor’s dedicated coolant feed and
exit lines.
Internally, the compressor motor compartment is separated and sealed from the main refrigerant
compression chamber. A double shaft seal on the motor side of the gear housing prevents cross
flow of refrigerant along the motor shaft. The motor coolant feed line is equipped with both a
solenoid valve and a check valve. These mechanical components, plus the higher pressure of the
liquid refrigerant, prevent back feed into the main refrigerant system. Refrigerant vapor exiting
the motor compartment must pass through a high pressure drop filter-drier. The filter-drier is
sized to immediately plug up and seal off the motor compartment. Both the coolant feed and
return lines are equipped with manual shutoff valves to permit component service.
Over 30 years of field experience have proven the reliability of these compressor motors. Despite
the reliability inherent in the motor design and the protective control, electrical distribution
system faults and lightning strikes can occur that are beyond the control of the most conscientious
designer. The McQuay motor coolant protective system protects the unit refrigerant charge from
being contaminated.
Figure 1, Motor Cooling