Electrical Machines The type of DC motor used for shears and punches is Differential compound motor. Shunt motor. Series motor. Cummulative compound motor. Differential compound motor. Shunt motor. Series motor. Cummulative compound motor. 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 1, 2, and 3 1, 2 and 4 2, 3 and 4 1 and 3 1, 2, and 3 1, 2 and 4 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 970 RPM 940 RPM 920 RPM 960 RPM 970 RPM 940 RPM 920 RPM 960 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 6 pole DC machine, 90 mechanical degrees correspond to which of the following electrical degree? 30. 45. 270. 180. 30. 45. 270. 180. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The fall in speed of the DC generator due to increase in load can be corrected by increasing the input to the prime mover. reducing the load voltage. increasing the excitation. cooling the armature. increasing the input to the prime mover. reducing the load voltage. increasing the excitation. cooling the armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In induction motor especially the cage rotors slots are nearly parallel to shaft axis. This is called crawling. cogging. skewing. slip. crawling. cogging. skewing. slip. ANSWER DOWNLOAD EXAMIANS APP
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