Electrical Machines For 250 volt DC Shunt Motor the armature and field resistance are 0.5 ohm and 250 ohm respectively. What will be the back e.m.f. produced when it takes a load current of 21A. 240 V. 280 V. 150 V. 220 V. 240 V. 280 V. 150 V. 220 V. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Air core transformer as compared to iron core transformer, has no magnetic core loss. more copper loss. less magnetic core loss. more magnetic core loss. no magnetic core loss. more copper loss. less magnetic core loss. more magnetic core loss. 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, 2, 3 and 4 are correct 1, 2 and 3 are correct 1 and 4 are correct 1, 2 and 4 are correct 2, 3 and 4 are correct 1, 2 and 3 are correct 1 and 4 are correct 1, 2 and 4 are correct ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 220 V dc machine has an armature resistance of 1Ω.If the full-load current is 20 A, the differenc in the induced voltages when the machine is running as a motor and as a generator is zero 20 V 50 V 40 V zero 20 V 50 V 40 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The current drawn by a DC motor at the time of starting is Very high. Normal. Zero. Very low. Very high. Normal. Zero. Very low. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the no-voltage release in a DC motor starter fails to operate on failure of supply, on resumption of supply the motor will develop very low starting torque. not start automatically. start automatically without trouble. get damaged. develop very low starting torque. not start automatically. start automatically without trouble. get damaged. ANSWER DOWNLOAD EXAMIANS APP
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