The efficiency of the copper oxide rectifier seldom exceeds________?
Correct answer
C. 65 to 75%
Explanation
The correct answer is 65 to 75%.
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Study 3,658 Electrical Engineering MCQs with correct answers and explanations.
Correct answer
C. 65 to 75%
Explanation
The correct answer is 65 to 75%.
Correct answer
D. Silicon
Explanation
The correct answer is Silicon.
Correct answer
D. back e.m.f. of rotor is more than the applied voltage
Explanation
Sure, let’s break it down. In a regenerative braking system, when the motor is acting as a generator, it generates an electromotive force (emf) due to the motion of the rotor. This emf is commonly referred to as the “back emf” because it opposes the applied voltage that’s trying to keep the motor running. Now, during regenerative braking, the motor’s rotor is still spinning, but the applied voltage is reduced or even reversed to slow down or stop the motor. Since the rotor is still in motion, it generates a back emf. For regenerative braking to be effective, this back emf needs to be greater than the applied voltage. This ensures that energy is being returned to the power source rather than being dissipated as heat in traditional braking systems. So, option C states that the back emf of the rotor is more than the applied voltage, which aligns with the principle of regenerative braking.
Correct answer
D. directional
Explanation
The correct answer is directional.
Correct answer
D. Either A. or B.
Explanation
The correct answer is Either A. or B..
Correct answer
C. only if the load current is not zero
Explanation
The correct answer is only if the load current is not zero.
Correct answer
A. low
Explanation
The correct answer is low.
Correct answer
A. load current
Explanation
The correct answer is load current.
Correct answer
A. short-circuit test only
Explanation
The correct answer is short-circuit test only.
Correct answer
A. short-circuit and overload
Explanation
The correct answer is short-circuit and overload.