Electrical Machines In dc machine armature windings are placed on rotor because of the necessity for generation of voltage. electromechanical energy conversion. commutation. development of torque. generation of voltage. electromechanical energy conversion. commutation. development of torque. 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, 2, and 3 1, 2 and 4 1 and 3 2, 3 and 4 1, 2, and 3 1, 2 and 4 1 and 3 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC shunt generator builds up 230 V when driven in clockwise direction. In case it is driven in anti clockwise direction, other things remaining unchanged, then the voltage build up is some what more than 230 V not possible 230 V some what less than 230 V some what more than 230 V not possible 230 V some what less than 230 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In which of the following motors DC excitation is not required? reluctance motor hysteresis motor 3-phase synchronous generator 3-phase synchronous motor reluctance motor hysteresis motor 3-phase synchronous generator 3-phase synchronous motor ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The flux involved in the emf equation of a transformer has rms value. total value. average value. maximum value. rms value. total value. average value. maximum value. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines It is advisable to start a DC series motor with some load to Avoid sparking. Limit the current. Limit the flux. Limit the speed. Avoid sparking. Limit the current. Limit the flux. Limit the speed. ANSWER DOWNLOAD EXAMIANS APP
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