Experimental Determination of Starting Capacitor Capacitance for a Refurbished Single-Phase Induction Motor

摘要

The refurbishment of a burnt laboratory 1.5kW single-phase induction motor was undertaken, with a view to demonstrating standard practice in the interest of both students and the rewinding workshop personnel. In this paper, a brief review of the capacitor induction motor is given. The necessary physical quantities from measurement/inspection of the motor useful in its design are detailed and the significant rewinding parameters are computed and duly specified. The laboratory test results and the concomitant calculations leading to the choice of capacitor are equally provided. The rewinding parameters realized included: the main concentric winding turns as 29, 25 and 19 of standard wire gauge (SWG) 20 (holding 3 wires in hand); auxiliary concentric winding turns as 62 and 54 of SWG 22 (holding 1 wire in hand); 4No. pole-belts for each operational winding; and 180o spreading of pole-belts. The selected capacitor was the electrolytic type whose capacitance was experimentally determined as 140uF. Observations from the workshop tests showed the motor as being capable of starting and running currents of 22A and 3.6A, respectively; and a no-load rotor speed of approximately 1500rpm.