초록 ▼

The compressor in a refrigeration system is controlled solely by a variable speed drive which controls the motor of the compressor by virtue of the varying of the frequency of the electricity provided to the motor. To minimize the initial cost and to minimize operating costs, the variable speed driv

The compressor in a refrigeration system is controlled solely by a variable speed drive which controls the motor of the compressor by virtue of the varying of the frequency of the electricity provided to the motor. To minimize the initial cost and to minimize operating costs, the variable speed drive is cooled by refrigerant from the refrigeration system which permits the use of a smaller drive, and the variable speed drive is operated at, or approaching, a unity power factor.

대표청구항 ▼

1. A refrigeration system having:a closed fluid circuit serially including a screw compressor, a discharge line, a condenser, an expansion device, a chiller and a suction line leading back to said compressor; water passing through said chiller in a heat exchange relationship and being cooled; said c

1. A refrigeration system having:a closed fluid circuit serially including a screw compressor, a discharge line, a condenser, an expansion device, a chiller and a suction line leading back to said compressor; water passing through said chiller in a heat exchange relationship and being cooled; said compressor being unloaded solely by regulating the speed of said compressor; motor means for driving said compressor; means for varying the speed of said motor means by controlling the frequency of electrical current supplied to said motor; means for providing cooling to said means for varying the speed; means for sensing the temperature of water leaving said chiller; means for controlling said means for varying the speed responsive to the sensed temperature of water leaving said chiller.