Industrial Drivers

31. In which of the following applications the load on motor changes in cyclic order?

1. Electric shovels
2. Cranes
3. Rolling mills
4. All of the above

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32. In which of the following applications variable speed operation is preferred?

1. Exhaust fan
2. Ceiling fan
3. Refrigerator
4. Water pump

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33. is not a part of ball bearing?

1. Inner race
2. Outer race
3. Cage
4. Bush

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34. Light duty cranes are used in which of the following?

1. Power houses
2. Pumping stations
3. Automobile workshops
4. All of the above

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35. method of starting a three phase induction motor needs six terminals.

1. Star-delta
2. Resistance starting
3. Auto-transformer
4. None of the above

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36. need frequent starting and stopping of electric motors,

1. Paper mills
2. Grinding mills
3. Air-conditioners
4. Lifts and hoists

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37. Reluctance motor is a

1. variable torque motor
2. low torque variable speed motor
3. self starting type synchronous motor
4. low noise, slow speed motor

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38. Rotor of a motor is usually supported on _________ bearings.

1. ball or roller
2. needle
3. bush
4. thrust

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39. s preferred for automatic drives.

1. Squirrel cage induction motor
2. Synchronous motors
3. Ward-Leonard controlled D.C. motors
4. Any of the above

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40. s preferred for synthetic fibre mills.

1. Synchronous motor
2. Reluctance motor
3. Series motor
4. Shunt motor

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