Q.1
What is the formula for the winding height in the design of the field windings?
  • a) winding height = height of the pole – height of shoe + space taken by the spool, flanges, etc
  • b) winding height = height of the pole + height of shoe + space taken by the spool, flanges, etc
  • c) winding height = height of the pole + height of shoe – space taken by the spool, flanges, etc
  • d) winding height = height of the pole – height of shoe – space taken by the spool, flanges, etc
Q.2
What is the approximate value of the space taken by spools, flanges, etc?
  • a) 15 mm
  • b) 10 mm
  • c) 12 mm
  • d) 20 mm
Q.3
What is the winding depth for the pole pitch of 0.1 mm?
  • a) 25 mm
  • b) 35 mm
  • c) 45 mm
  • d) 50 mm
Q.4
What is the formula for the voltage across each field coil?
  • a) voltage across each field coil = field current * resistance of each field at 75°C
  • b) voltage across each field coil = field current / resistance of each field at 75°C
  • c) voltage across each field coil = field current + resistance of each field at 75°C
  • d) voltage across each field coil = field current – resistance of each field at 75°C
Q.5
What is the range of the current density in the field conductors?
  • a) 3 to 5 A per mm2
  • b) 3 to 4 A per mm2
  • c) 4 to 5 A per mm2
  • d) 3 to 6 A per mm2
Q.6
What is the formula for the field current of the synchronous machines?
  • a) field current = current density * area of conductors
  • b) field current = current density / area of conductors
  • c) field current = current density – area of conductors
  • d) field current = current density + area of conductors
Q.7
What is the formula for the number of field turns of the field windings?
  • a) number of field turns = field mmf per pole at full load * field current
  • b) number of field turns = field mmf per pole at full load / field current
  • c) number of field turns = field mmf per pole at full load + field current
  • d) number of field turns = field mmf per pole at full load – field current
Q.8
What is the relation between winding space and the depth?
  • a) winding space is directly proportional to the depth
  • b) winding space is indirectly proportional to the depth
  • c) winding space is directly proportional to the square of the depth
  • d) winding space is indirectly proportional to the square of the depth
Q.9
What is the formula of the resistance of the winding is calculated at 75°C?
  • a) resistance of the winding = (Number of field turns * pole proportion * length of mean turns of the coil) / area of the field conductors
  • b) resistance of the winding = (Number of field turns * pole proportion * length of mean turns of the coil) * area of the field conductors
  • c) resistance of the winding = (Number of field turns / pole proportion * length of mean turns of the coil) / area of the field conductors
  • d) resistance of the winding = (Number of field turns * pole proportion / length of mean turns of the coil) / area of the field conductors
Q.10
What is the formula of the dissipating surface of the coil?
  • a) dissipating surface of the coil = 2*length of mean turns of the coil*(winding height * diameter of winding)
  • b) dissipating surface of the coil = 2*length of mean turns of the coil*(winding height / diameter of winding)
  • c) dissipating surface of the coil = 2*length of mean turns of the coil*(winding height + diameter of winding)
  • d) dissipating surface of the coil = 2*length of mean turns of the coil/(winding height * diameter of winding)
Q.11
What is the formula for the cooling co-efficient to the rotating field coils?
  • a) cooling coefficient of rotating field coils = 0.05 to 0.08 / 1 + armature voltage
  • b) cooling coefficient of rotating field coils = 0.05 to 0.08 / 1 – armature voltage
  • c) cooling coefficient of rotating field coils = 0.08 to 0.12 / 1 + armature voltage
  • d) cooling coefficient of rotating field coils = 0.08 to 0.12 / 1 – armature voltage
Q.12
What is the formula for the temperature rise in the design of field windings?
  • a) temperature rise = 1 / copper loss in each field coil at 75°C * cooling coefficient of rotating field coils * dissipating surface of the coil
  • b) temperature rise = copper loss in each field coil at 75°C * cooling coefficient of rotating field coils * dissipating surface of the coil
  • c) temperature rise = copper loss in each field coil at 75°C / cooling coefficient of rotating field coils * dissipating surface of the coil
  • d) temperature rise = copper loss in each field coil at 75°C * cooling coefficient of rotating field coils / dissipating surface of the coil
Q.13
If the temperature increases beyond the acceptable limits the depth of the winding should be decreased.
  • a) true
  • b) false
Q.14
The increase in the depth of the winding increases the heat dissipating surface.
  • a) true
  • b) false
Q.15
What is the minimum clearance between adjacent field coils and pole drawing?
  • a) 14 mm
  • b) 15 mm
  • c) 13 mm
  • d) 12 mm
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