Industrial Drivers

41. The capacity of a crane is expressed in terms of

1. type of drive
2. span
3. tonnes
4. any of the above

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42. The characteristics of drive for crane hoisting and lowering are which of the following?

1. Precise control
2. Smooth movement
3. Fast speed control
4. All of the above

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43. The cost of an induction motor will increase as

1. horsepower rating increases but r.p.m. decreases
2. horsepower rating decreases but r.p.m. increases
3. horsepower rating and operating speed increases
4. horsepower rating and operating speed decreases

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44. The diameter of the rotor shaft for an electric motor depends on which of the following?

1. r.p.m. only
2. Horse power only
3. Horse power and r.p.m.
4. Horse power, r.p.m. and power factor

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45. The load cycle for a motor driving a power press will be

1. variable load
2. continuous
3. continuous but periodical
4. intermittent and variable load

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46. The selection of an electric motor for any application depends on which of the following factors?

1. Electrical characteristics
2. Mechanical characteristics
3. Size and rating of motors
4. All of the above
5. All of the above

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47. The size of an excavator is usually expressed in terms of

1. 'crowd' motion
2. angle of swing
3. cubic metres
4. travel in metres

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48. The starting torque in case of centrifugal pumps is generally

1. less than running torque
2. same as running torque
3. slightly more than running torque
4. double the running torque

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49. The starting torque of a D.C. motor is independent of which of the following?

1. Flux
2. Armature current
3. Flux and armature current
4. Speed

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50. The travelling speed of cranes varies from

1. 20 to 30 m/s
2. 10 to 15 m/s
3. 5 to 10 m/s
4. 1 to 2.5 m/s

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