Operation Of Synchronous Motor at Constant Load Variable Excitation - MCQs

Operation Of Synchronous Motor at Constant Load Variable Excitation - MCQs

Q1. When the excitation of a synchronous motor is changed keeping the load constant then the

a. Power factor will change
b. I_a cos ∅ remains constant
c. Both (a) and (b)
d. None of the above

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Q2. Under excitation occurs when the magnitude of induced emf of synchronous motor is less than the applied voltage. During under excitation the current drawn by the motor and power factor

a. Increases, decreases and will be lagging in nature
b. Decreases, increases and will be leading in nature
c. Increases, increases and will be leading in nature
d. Decreases, decreases and will be lagging in nature

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Q3. If the field of the synchronous motor is overexcited then its power factor will be

a. Lagging
b. Leading
c. Unity
d. Zero

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Q4. For critical excitation the power factor of the synchronous motor will be equal to

a. 0
b. 1
c. 0.5
d. None of the above

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