Electrical Machines A 4-pole dc generator runs at 1500 rpm. The frequencyof current in the armature winding is 100 Hz 50 Hz 25 Hz 0 Hz 100 Hz 50 Hz 25 Hz 0 Hz 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 3, 4, 5 1, 2, 5 2, 3, 6 2, 4, 5, 6 3, 4, 5 1, 2, 5 2, 3, 6 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The power input to a 3 - φ induction motor is 60 kW and stator loss is 1 kW the rotor cu loss per phase is slip X 59 / 3. slip X 69 / 3. slip X 50 / 3. 1. slip X 59 / 3. slip X 69 / 3. slip X 50 / 3. 1. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines _____________ types of induction motor are widely used. Single phase IM. Squirrel cage IM. Slip ring IM. Three phase IM. Single phase IM. Squirrel cage IM. Slip ring IM. Three phase IM. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements about commutating poles which are fitted on most large dc Shunt motors: 1. The commutating poles are placed in the geometric neutral plane and their number is usually Equal to the number of main poles 2. The winding on the commutating poles is connected in series with the shunt-field winding on the main poles 3. The polarity of the commutating pole must be that of the next pole further ahead 4. The commutating poles neutralize the reactance voltage produced in the coil undergoing Commutation. Of these statements, 1, 2 and 4 are correct 2, 3 and 4 are correct 1 and 4 are correct 1, 2 and 3 are correct 1, 2 and 4 are correct 2, 3 and 4 are correct 1 and 4 are correct 1, 2 and 3 are correct ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the armature electric current is increased to double its previous value, and the time of commutation is halved, how will the reactance voltage vary? It will be halved. It will becomes four times. It will remain the same. It will be doubled. It will be halved. It will becomes four times. It will remain the same. It will be doubled. ANSWER DOWNLOAD EXAMIANS APP
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