Electrical Machines What is the necessity of copper brushes in a dc motors? To increase the flux cutting by the rotor. None of these. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. To increase the flux cutting by the rotor. None of these. To convert alternating supply current to direct current. To absorb the mechanical shocks produced during running condition. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For P pole machine relation between electrical degrees and mechanical degrees is θelec = 2/P*θmech θelec = P/2*θmech θelec = θmech θelec = 4/P*θmech θelec = 2/P*θmech θelec = P/2*θmech θelec = θmech θelec = 4/P*θmech ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 100 KVA transformer is operating at 60 Hz, 240 V supply. The same transformer is operating at 50 Hz, 200 V supply. The new rating is 50 KVA 123.3 KVA 83.33 KVA 100 KVA 50 KVA 123.3 KVA 83.33 KVA 100 KVA ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the field circuit of a DC shunt motor is opened DC Shunt Motor The armature current will reduce. The speed of motor will be reduced. The motor will attain dangerously high speed. DC Shunt Motor The armature current will reduce. The speed of motor will be reduced. The motor will attain dangerously high speed. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous motor electromagnetic power varies directly as applied voltage inversely as applied voltage None of these directly as square of applied voltage directly as applied voltage inversely as applied voltage None of these directly as square of applied voltage ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Short circuiting is caused in the armature winding due to grounding of two or more turns of the same coil. failure of insulation between two turns of coil. any of above. failure of insulation between two commutator bars. grounding of two or more turns of the same coil. failure of insulation between two turns of coil. any of above. failure of insulation between two commutator bars. ANSWER DOWNLOAD EXAMIANS APP
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