ELECTRICAL ENGINEERING DEPARTMENT
California Polytechnic State University
EE 255 Assignment #7
Problem #1
A 208V, threephase, 2pole, 60Hz Yconnected wound rotor induction motor is rated at 15
hp. Its equivalent circuit components are:
R
1
=0.2 Ohms
R
2
=0.12 Ohms
X
m
=15.0 Ohms
X
1
=0.41 Ohms
X
2
=0.41 Ohms
P
mech
=430 W
P
stray
=0
P
core
=0
Determine the slip at pullout torque and the pullout torque of this motor.
Problem #2
A 440V, threephase, 2pole, 50Hz Yconnected 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 Ohms
X
2
=0.17 Ohms
P
mech
=2.1 KW
P
stray
=150 W
P
core
=0
Determine the slip at pullout torque, the pullout torque, and the rotor speed at the pullout
torque of this motor.
Problem #3
If the motor in Problem 2 is to be driven from a 440V, 60 Hz power supply, what will
the pullout torque be? What will the slip be at pullout torque?
Problem #4
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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.
 Fall '11
 AliShaban
 Electrical Engineering

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