Q.1
What is the relation between number of poles and total volume of magnet?
  • a) number of poles is directly proportional to the total volume of the magnet
  • b) number of poles is indirectly proportional to the total volume of the magnet
  • c) number of poles is directly proportional to the square of the total volume of the magnet
  • d) number of poles is indirectly proportional to the square of the total volume of the magnet
Q.2
What is the relation between number of poles and flux reversal in the armature?
  • a) number of poles is directly proportional to the flux reversal in the armature
  • b) number of poles is indirectly proportional to the flux reversal in the armature
  • c) number of poles is directly proportional to the square of the flux reversal in the armature
  • d) number of poles is indirectly proportional to the square of the flux reversal in the armature
Q.3
How many number of poles should be used for large motors of relatively low speed?
  • a) should be equal to 2
  • b) should be lesser than 2
  • c) should be greater than 2
  • d) should be more than 4
Q.4
In the PMDC motors the brush shift should be approached with considerable caution.
  • a) true
  • b) false
Q.5
What is the relation of the brush shift with the demagnetization effect?
  • a) brush shift is directly proportional to the demagnetization effect
  • b) brush shift is indirectly proportional to the demagnetization effect
  • c) brush shift is directly proportional to the square of the demagnetization effect
  • d) brush shift is indirectly proportional to the square of the demagnetization effect
Q.6
How many primary reasons are present for the thermal failure?
  • a) 3
  • b) 4
  • c) 2
  • d) 5
Q.7
What does the increase of the resistance of the motor winding cause?
  • a) high starting current
  • b) low motor torque
  • c) low starting current
  • d) high motor torque
Q.8
What does the inability of the motor to dissipate the heat cause?
  • a) causes high starting current
  • b) insulation failure
  • c) causes low starting current
  • d) causes high starting current
Q.9
What is the solution to prevent the increase of resistance of motor windings?
  • a) higher ventilation arrangement
  • b) reduction in the number of poles
  • c) increase the coil windings
  • d) insulate the windings
Q.10
How many types of gears are made use of in the PMDC motors?
  • a) 1
  • b) 2
  • c) 3
  • d) 4
Q.11
What type of gears are used in the small loads and low inertia motors?
  • a) spur gears
  • b) helical gears
  • c) worm gears
  • d) worm gears and helical gears
Q.12
What type of gear is made use of in the high inertia motors?
  • a) spur gears
  • b) helical gears
  • c) worm gears
  • d) spur and helical gears
Q.13
What type of gear is made use for the silent operation?
  • a) spur gears
  • b) helical gears
  • c) worm gears
  • d) spur gears and worm gears
Q.14
How many types of bearings are made use of in the PMDC motors?
  • a) 2
  • b) 3
  • c) 4
  • d) 5
Q.15
How many principle types of lubricants are available in the PMDC motor?
  • a) 2
  • b) 3
  • c) 5
  • d) 7
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