# H_8 - b The angular velocity of the rotor mmf relative to...

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Homework Set #8 (ECE743) Problem 1: The windings of the device shown in Fig. 1 are sinusoidally distributed, each with N s equivalent turns. The bs winding may be arranged so that the bs axis is at an arbitrary angle α with the as axis. Express i as and i bs so that mmfs has a constant amplitude and rotates in the counterclockwise direction regardless of the value of α in particular, ) cos( 2 2 s e s s t I N mmfs φ ϖ - = . 1

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Problem 2: A two-phase induction motor is operating at a rated-load torque with balanced stator currents. The steady-state rotor speed is ϖ r = 0.9 ϖ e . it is an eight-pole, 50 Hz device. Determine the following: a) The actual rotor speed.
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Unformatted text preview: b) The angular velocity of the rotor mmf relative to the rotor. c) The frequency of the rotor currents. Problem 3: Determine the actual no-load and full-load speeds ( ϖ rm ) in revolutions per minute of the following device. a) A four-pole, three-phase 100 hp, 60 Hz, round-rotor synchronous machine. b) A 120-pole, three-phase 100 MW, 60 Hz, salient-pole synchronous machine. c) An eight-pole, two-phase 1 hp, reluctance machine supplied from a 5 Hz voltage source. d) A six-pole, three-phase 1/2 hp, permanent-magnet motor supplied from a 15 Hz voltage source. 2...
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H_8 - b The angular velocity of the rotor mmf relative to...

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