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Unformatted text preview: EE321 Exam 3A Spring 2004 Name: Student ID: Instructions: Work ALL Problems. Basic Problem 1 (11 pts) – Discrete Winding Function The number of conductors in the slots of a machine is given by [ ] 5 5 10 5 5 10 5 5 10 5 5 10 − − − − − − = as N How many poles the machine have ? Compute the winding function. Basic Problem 2 (12 pts) – Inductance Between Distributed Windings The winding function of two stator windings may be expressed ) cos( 12 s as w φ 4 = and ) 6 / 4 cos( 12 π φ − = s bs w . The radius and length of the machine are 5 cm and 20 cm, respectively, and the machine has an effective air gap of 2 mm. Determine the mutual inductance between the two windings. Basic Problem 3 (12 pts) – Rotating MMF The winding functions of the stator winding of a 2-phase machine are given by ) 8 cos( 5 s as w φ = and ) 8 sin( 5 s bs w φ − = . The stator currents are of the form ) 20 sin( 10 t i as = and ) 20 cos( 10 t i bs − = . The machine has an airgap of 2 mm. Express the B-field in the air gap do to the stator currents as a function of...
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- Spring '08
- Alternating Current, Inductor, Electric motor, Faraday's law of induction, Basic Problem, brushless dc machine