The brush-axis of a bipolar dc motor is rotated by 90°.
The effect of this rotation on the back emf Eb and the torque developed Td would be such that
A. both Eb and Td are unchanged
B. Eb is zero, but Td is unchanged
C. Eb is unchanged, but Td is zero
D. both Eb and Td are zero
Show Answer
Answer: D
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