4479 -- Efficiencies of an 11.2 kW Variable Speed Motor and Drive PDF

In this paper, energy efficiencies of an 11.2 kW (15 Hp) motor and pulse width modulated (PWM) drive over a wide range of operating conditions are reported. The effects of different parameters on these efficiencies are analyzed. The implications of these results for variable speed pumping systems are also discussed. Experimental results reveal that for a fixed drive switching frequency, component and system efficiencies vary with torque and speed, and both drive and motor efficiencies decrease at low torque. The drive switching frequency is shown to have a significant impact on both motor and drive efficiencies. Using measured data, a motor-drive system efficiency curve is generated for an ideal centrifugal load. This curve indicates that system efficiency decreases rapidly at low load conditions.

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