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 The use of permanent magnets gas air compressor unloader valve instead of rotor windings makes air 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 compressor housing, avoiding long unloader 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 startup in-rush current: less than 2 amps, compared with 500 to 600 amps for a traditional 75-ton, 460-v valve screw compressor with a cross-the-line gas air compressor unloader valve starter. [figure 1-2 omitted]when the magnetic bearings are energized, the motor and air and compressor impellers, which are keyed directly to the magnetic shaft, levitate. permanent-magnetic bearings do the primary work, while digitally controlled electromagnets provide the fine positioning. four positioning signals per bearing hold the levitated assembly to a tolerance of 0.00002 in. as the levitated assembly moves from the center point, the electromagnets'' intensity is adjusted to correct the position. these adjustments unloader occur 6 million times a minute. the software has been designed to automatically compensate valve for any out-of-balance condition in the levitated assembly.shutdowns and power gas failureswhen air the compressor is not running, the shaft assembly rests on graphite-lined, radially compressor located touchdown bearings. the magnetic unloader bearings normally position the rotor in the valve proper location, preventing contact between gas the rotor and other metallic surfaces. if the magnetic bearings fail, the touchdown bearings (also known as backup bearings) are used to prevent a compressor failure. with air and compressor the integration of the motor, unloader vsd, and magnetic-bearing system, valve the capacitors required for the motor and drive can gas be used as a backup power source for the bearings in the event of a power outage or emergency shutdown.capacity and efficiencyamong air 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 for retrofit compressor applications.efficiency improvements stem from a combination unloader 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. valve 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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