HIGH CAPACITY CHILLER COMPRESSOR

摘要

A high efficiency, low maintenance single stage or multi-stage centrifuga l compressor assembly for large cooling installations. The assembly is highl y efficient by virtue of a variable frequency drive (VFD) that drives a perm anent magnet motor and matches compressor speed with compressor load, a dire ct drive impeller that eliminates gearing losses, and magnetic bearings that reduce frictional losses. The back-emf produced by the motor provides an in termediate power source for the magnetic bearings in the event of a loss of electrical power. A cooling system provides direct cooling of the rotor with gas refrigerant, and cooling of the stator with liquid refrigerant. Modular construction allows the compressor to be retrofit with upgrades. An inlet g uide vane system operates without need for oil lubrication. The use of light metal castings and elimination of gearing reduces the weight to one-third o r less of comparably powered conventional units.