Electrical Machines What is the necessity of copper brushes in a dc motors? None of these. To absorb the mechanical shocks produced during running condition. To increase the flux cutting by the rotor. To convert alternating supply current to direct current. None of these. To absorb the mechanical shocks produced during running condition. To increase the flux cutting by the rotor. To convert alternating supply current to direct current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a synchronous machine, if the field flux axis is ahead of the armature field axis in the direction of rotation, the machine operating is asynchronous motor. synchronous motor. asynchronous generator. synchronous generator. asynchronous motor. synchronous motor. asynchronous generator. synchronous generator. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ω. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is 0.87 0.95 1.06 0.96 0.87 0.95 1.06 0.96 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Find the number of poles required, when the frequency is 50Hz and speed of the motor is 500 rpm? 5 10 24 12 5 10 24 12 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Maximum power developed by a synchronous motor depends on supply voltage and load angle excitation and load angle supply voltage, load angle and excitation supply voltage and excitation supply voltage and load angle excitation and load angle supply voltage, load angle and excitation supply voltage and excitation ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A separately-excited DC generator, running at rated speed, has 6 volts across its armature terminals with no field current. When field winding is excited with one ampere, the voltage builds up to 250 V at no load. In case field current is reduced to zero, with the speed remaining unaltered, the armature terminal voltage would be 6 V less than 6 V zero more than 6 V 6 V less than 6 V zero more than 6 V ANSWER DOWNLOAD EXAMIANS APP
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