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ee341_h05_Wi2012

# ee341_h05_Wi2012 - X 1 =0.503 ohm Xm=13.25 ohm R 2 =0.144...

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ECE 341 Homework #5 Due: Mar. 2, Feb. 12 Problem 1 : An eight-pole, 60 Hz, 3-phase, wye-connected induction motor has mechanical losses of 620 W at s=0.04. At the same time, the motor delivers 30 HP at its shaft. Calculate (a) the input power to the rotor (P AG ) (2 points) (b) the load torque and total torque (2 points) Problem 2: A six-pole, 480 V, 3-phase, 60 Hz induction motor takes 200 A of current in each phase at starting, and 30 A/Phase when it runs with full load. The starting torque is 1.8 times the torque at the full load at 480 V. If it is desired that the starting torque be the same as the full load torque, determine (a) The applied line-to-line voltage (2 points) (b) The corresponding line current (phase) of the motor (2 points) Problem 3: A three phase, wye-conneted, 220 V, 10 HP, 60 Hz, 6-pole induction motor has the following constants: R 1 =0.294 ohm
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Unformatted text preview: X 1 =0.503 ohm Xm=13.25 ohm R 2 =0.144 ohm X 2 =0.209 ohm (stator side referred) When the motor is operated at rated voltage and rated frequency, the slip rate is 0.02, the total friction-windage losses are 403 W, ignore the core loss, calculate (a) Rotor speed (2 points) (b) Load power and torque (2 points) (c) Stator current, stator power factor (2 points) Problem 4: For a boost converter shown in the Figure, assuming C is big enough to hold constant voltage, at the following conditions: 200 L uH, 180 in V V, D=0.4, 5 R , Ts=100 us; 1) Calculate the inductor peak to peak current ripple; (2 points) 2) Calculate the DC component of L i ; (2 points) 3) Draw the inductor current L i , switch current 1 S i , diode current D i , switch voltage 1 S V , and switching status (2 Points) out V S1 L i in V C R L 1 S i D i +-1 S V +-+-...
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