Electrical Machines A load of 900 lbs is to be raised with a lift car weighting 855 lbs at a speed of 110 feet per minute, the over balance being 40 % and percentage efficiency 45 %. Find the horse power of the motor without counterweight 150. 160. 180. 170. 150. 160. 180. 170. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the necessity of copper brushes in a dc motors? To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. None of these. To convert alternating supply current to direct current. To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. None of these. To convert alternating supply current to direct current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To increase starting torque of a 3-phase slip ring induction motor, preferred method is to increase supply frequency None of these supply voltage rotor resistance supply frequency None of these supply voltage rotor resistance ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Find the synchronous reactance of alternators in which a given field current of 200 A on short circuit and a generated emf of 50 V on open circuit. Armature resistance is 0.1 ohm 0.23Ω. 1Ω. 0.5Ω. 0.25Ω. 0.23Ω. 1Ω. 0.5Ω. 0.25Ω. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In synchronous generator, inverted V curve is drawn between field current on Y-axis and power factor on X-axis field current on X-axis and power factor on Y-axis field current on Y-axis and armature current on X-axis field current on X-axis and armature current on Y-axis field current on Y-axis and power factor on X-axis field current on X-axis and power factor on Y-axis field current on Y-axis and armature current on X-axis field current on X-axis and armature current on Y-axis ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Short circuiting is caused in the armature winding due to any of above. grounding of two or more turns of the same coil. failure of insulation between two commutator bars. failure of insulation between two turns of coil. any of above. grounding of two or more turns of the same coil. failure of insulation between two commutator bars. failure of insulation between two turns of coil. ANSWER DOWNLOAD EXAMIANS APP
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