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 The use of permanent magnets northstar132cfm90psi55hpaircompressormodel45921 instead of rotor windings makes the motor smaller and lighter than induction motors. Using magnetic-bearing technology, a 75-ton compressor weighs 265 lb--about one-fifth the weight of a conventional compressor.A variable-speed drive (VSD) is required for the motor to operate. The VSD varies the frequency between 300 and 800 Hz, which provides a compressor-speed range from 18,000 to 48,000 rpm. This avoids a gear set. The VSD is integrated into the compressor housing, avoiding long leads and allowing key electronic components to be refrigerant-cooled. The VSD also acts as a soft starter; as a result, the compressor has an extremely low northstar132cfm90psi55hpaircompressormodel45921 startup in-rush current: less than 2 amps, compared with 500 to 600 amps for a traditional 75-ton, 460-v screw compressor with a cross-the-line starter. With the integration of the motor, VSD, and magnetic-bearing system, the capacitors required for the motor and drive can be used as a backup northstar132cfm90psi55hpaircompressormodel45921 power source for the bearings in the event of a power outage or emergency shutdown.CAPACITY AND EFFICIENCYAmong the key parameters affecting performance are capacity (tons) and efficiency (kilowatts per ton). The compressor''s capacity ranges from 60 to 90 tons, depending on the operating conditions. Plans call for that range to be extended to 150 tons water-cooled and 115 tons air-cooled by the end of 2004 with the use of R-134a refrigerant. An R-22 version is planned northstar132cfm90psi55hpaircompressormodel45921 for retrofit applications.Efficiency northstar132cfm90psi55hpaircompressormodel45921 improvements stem from a combination of the centrifugal compressor, permanent-magnet motor, and magnetic bearings. Within the compressor, efficiency is affected by the compressor isentropic efficiency (the efficiency of the wheels), the motor, and the bearings. Traditional induction motors of this size typically are in the 92-percent efficiency range. This compressor''s permanent-magnet motor has an efficiency of 96 to 97 percent. Buy a gas air compressor with us and save a TON of cash. Our selection of cheap gas air compressors is second to none.
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