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Unformatted text preview: EE321 Exam 2A Spring 2004 Name: Student ID: Instructions: Work ALL Basi Problems. Basic Problem 1 (11 pts) – VR Stepper Motor Equilibrium Points With a certain combination of currents, the torque produced by a variable reluctance stepper motor may be expressed as ) 12 . 4 cos( 23 . − = rm e T θ where all terms in the argument of the cosine are in radians. The load torque is 0.1 Nm. Determine a stable equilibrium point. Determine an unstable equilibrium point. Basic Problem 2 (12 pts) – VR Stepper Motor Parameter Identification A sinusoidal voltage of 20 V rms magnitude and with a frequency of 100 Hz is applied to a VR stepper. As the rotor is turned very slowly, the current varies from a maximum of 2 A rms in magnitude to a minimum of 200 mA rms in magnitude. The resistance of the motor windings is 1 Ω. Determine b L . Basic Problem 3 (12 pts) – PM DC Machine The parameters of a permanent magnet dc machine are Ω = 1 ....
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This note was uploaded on 02/19/2012 for the course ECE 321 taught by Professor Staff during the Spring '08 term at Purdue.
- Spring '08