7-Assignment7_Solution

7-Assignment7_Solution - ELECTRICAL ENGINEERING DEPARTMENT...

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Unformatted text preview: ELECTRICAL ENGINEERING DEPARTMENT California Polytechnic State University EE 255 Assignment #7 Solution Problem #1 A 208-V, three-phase, 2-pole, 60-Hz Y-connected wound rotor induction motor is rated at 15-hp. Its equivalent circuit components are: R 1 =0.2 Ohms R 2 =0.12 OhmsX m =15.0 Ohms X 1 =0.41 OhmsX 2 =0.41 Ohms P mech =250 W P stray =0 P core =180 W Determine the slip at pullout torque and the pullout torque of this motor. Solution: Th Th Th Th jX R j Z j j j Z + = + = = = + + = 4 189 74 64 444 3 89 41 15 154 84 6 41 15 2 41 2 15 . . . . . . . . . ) . . )( ( V j V Th = = 7 8 116 3 89 41 15 15 120 . . . . ) ( % . * . . ) . . ( . . ) ( max max max 4 14 100 144 144 41 4 189 12 2 2 2 2 2 2 = = = + + = + + = T T Th Th T S S X X R R S m N T X X R R V T Th Th Th s Th- = + + = + + + = 2 53 81 189 189 377 8 116 5 1 5 1 2 2 2 2 2 2 2 . ] . . . [ ) . ( . ] ) ( [ . max max Problem #2 A 440-V, three-phase, 2-pole, 50-Hz Y-connected wound rotor induction motor is rated at 75 KW. Its equivalent circuit components are: R 1 =0.075 Ohms R 2 =0.065 Ohms X m =7.2 Ohms X 1 =0.17 OhmsX 2 =0.17 Ohms P mech =1.0 KW W P stray =150 W P core =1.1 KW Determine the slip at pullout torque, the pullout torque, and the rotor speed at the pullout torque of this motor....
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This note was uploaded on 12/19/2011 for the course EE 295 taught by Professor Alishaban during the Fall '11 term at Cal Poly.

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7-Assignment7_Solution - ELECTRICAL ENGINEERING DEPARTMENT...

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