Which D.C. motor bas got maximum self loading property? Mark as favorite Copy Link Series motor Shunt motor Cumulatively compounded motor Differentially compounded motor Check Answer
Which of the following can be used for controlling the speed of a D.C. motor? Mark as favorite Copy Link Thermistor Transistor Thyratron Thyristor Check Answer
In a D.C. shunt motor, speed is? Mark as favorite Copy Link independent of armature current directly proportional to the armature current proportional to the square of the current inversely proportional to the armature current Check Answer
The hysteresis loss in a D.C. machine least depends on? Mark as favorite Copy Link Frequency of magnetic reversals Maximum value of flux density Volume and grade of iron Rate of flow of ventilating air Check Answer
A brake test on D.C. motors is usually restricted to? Mark as favorite Copy Link small horse power motors variable speed motors high speed motors open frame type motors Check Answer
In hazardous area of gassy mines, material transportation is done by vehicles powered by? Mark as favorite Copy Link A.C. mains D.C. mains I.C. Engines batteries Check Answer
If the supply voltage for a D.C. motor is increased, which of the following will decrease? Mark as favorite Copy Link Starting torque Operating speed Full-load current All of the above Check Answer
The generated e.m.f and the current are in the opposite direction in case of? Mark as favorite Copy Link d.c. generators d.c. motors both (a) and (b) none of the above Check Answer
While starting a differential compound motor, it is best to short the series field in order to avoid? Mark as favorite Copy Link excessive starting period motor starting in wrong direction tripping of the circuit breaker large in rush of current Check Answer
In electric motors carbon brushes are used to? Mark as favorite Copy Link provide a path for flow of current prevent sparking during commutation prevent overheating of armature windings brush off carbon deposits on the commutator Check Answer