Electrical Machines Counter emf of a DC motor regulates its armature voltage. helps in energy conversion. exceeds supply voltage aids applied voltage. regulates its armature voltage. helps in energy conversion. exceeds supply voltage aids applied voltage. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In star-delta starting of squirrel cage induction motor compared to DOL starting the starting current and torque are 1/3, 1/√3 1/√3, 1/3 1/3, 1/3 1/√3, 1/√3 1/3, 1/√3 1/√3, 1/3 1/3, 1/3 1/√3, 1/√3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a seperately excited DC Motor if field current is increased, it will Reduce starting torque. Reduce armature heating. Increase speed Increase acceleration duration. Reduce starting torque. Reduce armature heating. Increase speed Increase acceleration duration. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two DC series motors are connected in series and are driving the same mechanical load. If the motors are now connected in parallel the speed will become one fourth. double. 4 times. half. one fourth. double. 4 times. half. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The counter (or back) emf in a dc machine is 1. the same as generated emf in a dc motor 2. proportional to field flux and armature speed 3. not the same as generated emf in a dc motor 4.inversely proportional to field flux 5. proportional to number of armature conductors 6. constant from no load to full load From these, the correct answer is 2, 4, 5, 6 1, 2, 5 2, 3, 6 3, 4, 5 2, 4, 5, 6 1, 2, 5 2, 3, 6 3, 4, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A transformer has resistance and reactance in per unit as 0.01 and 0.04 respectively. Its voltage regulation for 0.8 power factor lagging and leading will be 3.2% and -1.6% 6% and -4% 4.8% and -3.2% None of these 3.2% and -1.6% 6% and -4% 4.8% and -3.2% None of these ANSWER DOWNLOAD EXAMIANS APP