Electrical Machines If s is the slip and f is the supply frequency of an induction motor, the frequency of rotor current is given by f / s. s2. sf. sf / 2. f / s. s2. sf. sf / 2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To have sparkless commutation, the armature reaction effect in a DC machine is neutralized by shifting the brush axis from GNA to MNA. fixing the brush axis inline with the pole axis. compensating winding and commutating poles. increasing field excitation. shifting the brush axis from GNA to MNA. fixing the brush axis inline with the pole axis. compensating winding and commutating poles. increasing field excitation. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two 3-phase AC generators are such that one has twice the linear dimensions of the other. The field windings of each are excited to give identical sinusoidal air-gap flux density waveform. Both have the same number of stator slots and identical winding patterns. The conductor/slot in a big generator is K times that of the smaller one. The value of K to get equal no load voltage at same frequency is 1/2. 1/4. 4. 8. 1/2. 1/4. 4. 8. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a seperately excited DC Motor if field current is increased, it will Increase acceleration duration. Reduce armature heating. Increase speed Reduce starting torque. Increase acceleration duration. Reduce armature heating. Increase speed Reduce starting torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If field current is decreased in shunt dc motor, the speed of the motor decreases. None of these increases. remains same. decreases. None of these increases. remains same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The speed of a DC series motor is Proportional to field current. Proportional to the armature current. Proportional to the square of the armature current. Inversely proportional to the armature current. Proportional to field current. Proportional to the armature current. Proportional to the square of the armature current. Inversely proportional to the armature current. ANSWER DOWNLOAD EXAMIANS APP
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