16 Product Manual PM WSC/WDC
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 fault will not pass into the main refrigerant circuit. Moisture, acid and/or carbon particles would be
automatically trapped within the 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 within the
compressor. 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 backfeed into the main
refrigerant system. Refrigerant vapor exiting the motor compartment must pass through an undersized
combination filter-drier. The filter-drier is sized to immediately plug up and seal off the motor compartment in
case of a motor burnout. 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
intended by the motor design and the protective control, electrical distribution system faults and lightning
strikes may occur that are beyond the control of the most conscientious designer. The motor coolant’s
protective system protects the system. A motor failure will not contaminate the common refrigerant circuit or
prevent normal operation of the second compressor.
Part Load Efficiency
Chillers usually spend 99% of their operating hours under part load conditions, and as illustrated on page 4,
most of this time at less that 60% of design capacity. One compressor of a dual chiller operates with the full heat
transfer surface of the entire unit, for example, one 500 ton (1,750 kW) compressor on a 1,000 ton (3,500 kW)
To Next Page
Loading...
Need help?
General
