Electrical Machines The sparking at the the brushes, in a DC machines is due to armature reaction. presence of commutator. high resistance of carbon brushes. reactance voltage. armature reaction. presence of commutator. high resistance of carbon brushes. reactance voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4-pole DC generator runs at 1500 rpm. The frequency of current in the armature winding is: Zero Hz. 50 Hz. 25 Hz. 100 Hz. Zero Hz. 50 Hz. 25 Hz. 100 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The core flux in transformer depends mainly on supply voltage, frequency and load supply voltage supply voltage and load supply voltage and frequency supply voltage, frequency and load supply voltage supply voltage and load supply voltage and frequency ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 2, 3, 4, 5 2, 3, 4 1, 2, 3 2, 3 ,5 2, 3, 4, 5 2, 3, 4 1, 2, 3 2, 3 ,5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The supply voltage to an induction motor is reduced by 10%. By what percentage, approximately, will the maximum torque decrease? 19% 10% 5% 40% 19% 10% 5% 40% ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3 - φ induction motor running at full load which of these parameters is stationary with respect to the stator mmf wave? Stator winding. Both rotor and stator winding. Rotor mmf wave. Rotor winding. Stator winding. Both rotor and stator winding. Rotor mmf wave. Rotor winding. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS