Which of the following resistances can be measured by conducting insulation resistance test on a synchronous motor ? A. Phase to phase winding resistance B. Stator winding to earthed frame C. Rotor winding to earthed shaftD. All of the above

The speed of a synchronous motor: A. increases as the load increases B. decreases as the load decreasesC. always remains constant D. none of the above

When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way A. augments it directlyB. directly opposes it C. cross-magnetises it D. none of the above

If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor__________? A. become moreB. become less C. remain constant D. none of the…

Change of D.C. excitation of a synchronous motor changes: A. applied voltage of the motorB. power factor of power drawn by the motor C. motor speed D. none of the these E. all of the these

The mechanical displacement of the rotor with respect to the stator, in polyphase multipolar synchronous motors running at full load, is of the order of_____________? A. zero degree B. two degreesC. five degrees D. ten degrees

An important advantage of a synchronous motor over wound round induction motor is that A. its power factor may be varied at will B. its speed is independent of supply frequency C. its speed may be controlled more easily D.…

The angle between the rotating stator flux and rotor poles is called _________ angle. A. synchronizing B. obtuseC. torque D. power factor

Slip-rings in a synchronous motor carry____________? A. direct current B. alternating current C. no current D. all of the above

A synchronous motor working at leading power factor can be used as____________? A. voltage boosterB. phase advancer C. noise generator D. mechanical synchronizer