Electrical Machines A 220 V DC generator is run at full speed without any excitation. The open circuit voltage will be 220 V. zero. about 50 V. about 2 V. 220 V. zero. about 50 V. about 2 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The demagnetising component of armature reaction in a DC generator increases armature speed. reduces generator emf. results in sparking trouble. reduces inter poles flux density. increases armature speed. reduces generator emf. results in sparking trouble. reduces inter poles flux density. 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 0.96 1.06 0.87 0.95 0.96 1.06 0.87 0.95 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When R2 is rotor resistance, X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running condition will be sR2 = X2. R2 = s2X2. R2 = s2X2. R2 = sX2. sR2 = X2. R2 = s2X2. R2 = s2X2. R2 = sX2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An induction motor having 8 poles runs at 727.5 rpm. If the supply frequency is 50Hz, the emf in the rotor will have a frequency of 48.5Hz 1.5Hz 51.5Hz 2.5Hz 48.5Hz 1.5Hz 51.5Hz 2.5Hz ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Current in a coil undergoing commutation is not able to get reversed completely by the end of commutation period. It is due to reactance voltage induced in the coil. coil resistance. None of these armature emf. reactance voltage induced in the coil. coil resistance. None of these armature emf. ANSWER DOWNLOAD EXAMIANS APP
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