Electrical Machines The brush-axis of a bipolar dc motor is rotated by 90°. The effect of this rotation on the back emf Eband the torque developed Tdwould be such that both Eb and Td are zero Eb is zero, but Td is unchanged both Eb and Td are unchanged Eb is unchanged, but Td is zero both Eb and Td are zero Eb is zero, but Td is unchanged both Eb and Td are unchanged Eb is unchanged, but Td is zero ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the back emf in DC motor vanishes suddenly the motor will start haunting. run at very low speed. run at very high speed. burn. start haunting. run at very low speed. run at very high speed. burn. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a dc machine, 1. physically, the brush axis is along the direct axis 2. physically, the brush axis is along the interpolar axis 3. schematically, the brush axis is along the direct axis 4. schematically, the brush axis is along the quadrature axis 5. armaturemmf is directed along the brush axis From these, the correct statements are 2, 4, 5 2, 3, 5 1 , 3, 5 1, 4,5 2, 4, 5 2, 3, 5 1 , 3, 5 1, 4,5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The heat transfer by convection in a transformer least depends on temperature difference. color of the paint. air velocity. surface area. temperature difference. color of the paint. air velocity. surface area. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines What is the effect of armature reaction ? Armature flux distorts the main field flux. Armature flux weakens the main field flux. None of the options. Both option B and C. Armature flux distorts the main field flux. Armature flux weakens the main field flux. None of the options. Both option B and C. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In single phase rotary converter the number of slip rings will be four. six. two. three. four. six. two. three. ANSWER DOWNLOAD EXAMIANS APP
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