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A motor is designed to operate on 117 V and draws a current of 12.3 A when it first starts up. At its normal operating speed, the motor draw
Question
A motor is designed to operate on 117 V and draws a current of 12.3 A when it first starts up. At its normal operating speed, the motor draws a current of 3.38 A. Obtain (a) the resistance of the armature coil, (b) the back emf developed at normal speed, and (c) the current drawn by the motor at one-third normal speed
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Physics
5 years
2021-08-12T07:31:46+00:00
2021-08-12T07:31:46+00:00 1 Answers
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Answers ( )
Answer:
a) using
R=V/I =117/12.3
R=9.5 ohms
b)
E=V-I*R =117-3.38*9.5
E=84.8Volts
c)
at (1/3)rd of normal speed ,back emf is (1/3) of its maximum
value
E=(1/3)*84.8=28.3Volts
Current drawn
I=V-Eback/R =117-28.3/9.5
I=9.33A
Explanation: