EE321 Spring 2009 Homework 12 Problem 54 – Rotating MMF Using the configuration we studied in class (Figure 5.2-1 in text), the stator currents of a 4 pole machine are given by )200cos(50)200sin(50titibsas-==The speed of the machine is 500 rpm in the CW direction. What is the physical speed and direction of the stator MMF as viewed from the rotor. Problem 55 – Phase Inductance Suppose the winding function of a-phase of the stator is given by =smsasPNPwφ2cos2and the winding function of the b-phase of the rotor is given by =rmrbrPNPwφ2sin2Express the mutual inductance between the a-phase stator and b-phase rotor windings in terms of sN, rN, P, the rotor radius r, the rotor length L, the airgap g, the permeability of free space 0μand electrical rotor position rθ. Problem 56 – QD Transformation Show in detail that msssTsrsrLKLK=-1'where 'srLis given by (5.3-48) and msLis given by (5.5-23).
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Trigraph, Physical quantities, Inductor, Electric motor