Electrical Machines A self-excited shunt generator fails to build up, because 1. the field circuit is open 2. The armature circuit is open 3. the residual magnetism is absent 4. The direction of rotation is wrong From these, the correct answer is 1, 2 and 3 3 only 1, 2, 3 and 4 1, 3 1, 2 and 3 3 only 1, 2, 3 and 4 1, 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The oscillation in a synchronous motor can be damped out by running the motor on leading power factors. oscillation cannot be damped. maintaining constant excitation. providing damper bars in the rotor pole faces. running the motor on leading power factors. oscillation cannot be damped. maintaining constant excitation. providing damper bars in the rotor pole faces. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Transformer cooling and insulating oil must be of low resistivity. low viscosity. low BDV. high viscosity. low resistivity. low viscosity. low BDV. high viscosity. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Unbalance 3 - Φ stator currents cause double frequency currents in the rotor. vibrations. All of these heating of rotor. double frequency currents in the rotor. vibrations. All of these heating of rotor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The slip of an induction motor during DC rheostatic braking is s. 2 + s. 2 - s. 1 - s. s. 2 + s. 2 - s. 1 - s. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the armature electric current is increased to double its previous value, and the time of commutation is halved, how will the reactance voltage vary? It will be doubled. It will remain the same. It will becomes four times. It will be halved. It will be doubled. It will remain the same. It will becomes four times. It will be halved. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS