Electrical Machines The speed of stator rotating magnetic field (RMF) with respect to rotor is S.Ns Nr Ns Zero S.Ns Nr Ns Zero ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following factors improve commutation in a dc machine ? 1. High contact resistance of brushes 2. High inductance of the coils undergoing commutation 3. Shifting of brushes in the direction of rotation for a generator and in the opposite direction For a motor 4. Narrow width for the commutation bars Select the correct answer using the codes given below : Codes : 1 and 3 2, 3 and 4 1, 2 and 4 1, 2, and 3 1 and 3 2, 3 and 4 1, 2 and 4 1, 2, and 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In circle diagram for induction motor, diameter of circle represents which of the following ? Slip. Line voltage. Rotor current. Running torque. Slip. Line voltage. Rotor current. Running torque. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To achieve spark less commutation brushes of DC generator are rocked ahead so as to bring them in magnetic neutral axis. just behind the magnetic neutral axis. just ahead of magnetic neutral axis. None of these in magnetic neutral axis. just behind the magnetic neutral axis. just ahead of magnetic neutral axis. None of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The flux involved in the emf equation of a transformer has rms value. average value. maximum value. total value. rms value. average value. maximum value. total value. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature resistance of a permanent magnet dc motor is 0.8 Ohm. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the same source will be 88.8%. 48.0%. 57.1%. 59.2%. 88.8%. 48.0%. 57.1%. 59.2%. ANSWER DOWNLOAD EXAMIANS APP
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