Synchronous motors Archives

31. Which of the following motors is non-self starting ?

D.C. series motor

synchronous motor

series motor B. synchronous motor C. Squirrel cage induction motor

Wound round induction motor

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32. A synchronous motor can be started by

pony motor

compound motor C. providing damper winding

any of the above

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33. A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will

remain same

go down

improve

none of the above

Detailed SolutionA synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the

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synchronous motor goes down, the power factor of the synchronous motor will

34. The speed regulation of a synchronous motor is always

0.50%

positive

zero

Detailed

Solution

35. A rotory converter can also be run as a

d.c. shunt motor

d.c. series motor

d.c. compound motor

induction motor E. synchronous motor

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36. If one-phase of a 3-phase synchronous motor is short-circuited, motor

will refuse to start

will overheat in spots

will not come upto speed

will fail to pull into step

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37. The construction of a synchronous motor resembles

a series motor

an induction motor

an alternator

a rotary converter

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38. As the load is applied to a synchronous motor, the motor takes more armature current because

The increased load has to take more current

The rotor by shifting its phase backward causes motor to take more current

The back e.m.f. decreases causing an increase in motor current

The rotor strengthens the rotating field causing more motor current

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a synchronous motor, the motor takes more armature current because" class="read-more button" href="https://exam.pscnotes.com/mcq/as-the-load-is-applied-to-a-synchronous-motor-the-motor-takes-more-armature-current-because/#more-53066">Detailed Solution