For higher values of armature, the speed of a DC series motor is Proportional to armature current. Inversely proportional to armature current. Proportional to the square of armature current. Constant. TRUE ANSWER : ? YOUR ANSWER : ?
If the source voltage of a DC motor is increased, which of the following will decrease? Starting torque. Operating speed. Starting torque, operating speed, full load current. Full load current. TRUE ANSWER : ? YOUR ANSWER : ?
When Flemings right hand rule to find the direction of induced emf, the thumb points towards opposite to the direction of motion of the conductor. direction of motion of the conductor. direction of flux. direction of induced emf. TRUE ANSWER : ? YOUR ANSWER : ?
When a short circuit test on a transformer is performed at 25 V, 50 Hz, the drawn current is I1. If the test is performed by 25 V and 25 Hz and power drawn current is I2, then I1 = I2 I1 > I2 None of these I1 < I2 TRUE ANSWER : ? YOUR ANSWER : ?
In case of DC Shunt Motor, the speed will____ if the voltage increases, neglecting armature saturation. remain the same. decrease. be unpredictable. increase TRUE ANSWER : ? YOUR ANSWER : ?
If the applied voltage of a certain transformer is increased by 50% and the frequency is reduced by 50%, the maximum flux density will (assuming that the magnetic circuit remains unsaturated) changes to three times the original value changes to 0.5 times the original value changes to 1.5 times the original value remain the same as the original TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following is not a necessary condition to be satisfied for synchronising an incoming alternator to an already operating alternator? same phase sequence same voltage magnitude same prime mover speed same frequency TRUE ANSWER : ? YOUR ANSWER : ?
Why are capacitors used with large AC induction motor? Improve power factor. Improve current level. Improve voltage level. Improve power level. TRUE ANSWER : ? YOUR ANSWER : ?
In a dc generator operating on load with its brushes on the geometrical neutral axis (GNA), the magnetic neutral axis (MNA) is shifted in the direction of rotation. Now, if the brushes are given a lead of 90° (electrical), then the MNA will shift forward by less than 90° shift forward by 90° coincide with the GNA shift forward by more than 90° TRUE ANSWER : ? YOUR ANSWER : ?
A simple method of increasing the voltage of a DC generator is to increase the number of turns in armature coil. increase the number of turns in field coil. increase the speed of shaft rotation. increase the source frequency. TRUE ANSWER : ? YOUR ANSWER : ?