| 1. | The speed of a D.C. shunt motor is required to be more. than full load speed. This is possible by ? | |
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reducing the field current
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decreasing the armature current
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increasing the armature current
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increasing the excitation current
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Report Question| 2. | In a D.C. motor, the ratio E¡/V4 indicates ? | |
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running torque of the motor
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starting torque of the motor
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efficiency of the motor
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speed regulation of the motor
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| 3. | Which of the following is not necessarily the advantage of D.C. motors over A.C. motors ? | |
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Better speed control
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Low cost
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High starting torque
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Wide speed range
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| 4. | Regenerative braking on D.C. shunt motors is used when ? | |
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the load has overhauling characteristics
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the load is variable
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the load also acts as a braking force
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the load is constantly decreasing
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| 5. | The function of a field regulator for compound motors is to ? | |
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control the flux
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limit the armature current
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demagnetise the field partially
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none of the above
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| 6. | Which of the following tests can be used to determine no-load losses in a D.C. shunt motor ? | |
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Running down test
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Swinburne's test
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Field test
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Brake test
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| 7. | D.C. generators are installed near the load centres to reduce ? | |
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iron losses
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line losses
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sparking
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corona losses
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| 8. | In Ward Leonard method of speed control of a D.C. motor, change in speed of motor is obtained by the ? | |
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change in armature voltage of D.C. motor
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change in the field excitation of the D.C. motor
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change in armature current of the D.C. motor
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change in supply voltage
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| 9. | What will happen if the back e.m.f. of a D.C. motor vanishes suddenly ? | |
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The motor will stop
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The motor will continue to run
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The armature may burn
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The motor will run noisy
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| 10. | Usually wide and sensitive speed control is desired in case of ? | |
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centrifugal pumps
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elevators
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steel rolling mills
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colliery winders
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