Design of Electrical Machines Practice Test 8

1. How many kinds of single phase windings are present?

2. What is the formula of the rotor teeth flux density?

flux density of rotor teeth = maximum flux / (number of rotor slots / number of poles) * length of the teeth * depth of rotor core

flux density of rotor teeth = maximum flux * (number of rotor slots / number of poles) * length of the teeth * depth of rotor core

flux density of rotor teeth = maximum flux / (number of rotor slots * number of poles) * length of the teeth * depth of rotor core

flux density of rotor teeth = 1/maximum flux * (number of rotor slots / number of poles) * length of the teeth * depth of rotor core

3. What is the range of the ratio of the total cross section of rotor bars to the total stator copper section for main winding for aluminium?

1.2-1.5

1-1.6

1-1.3

1-1.4

4. When is the skein winding made use of?

when large amount of relatively large size wire is used

when large amount of relatively small size wire is used

when small amount of relatively small size wire is used

when small amount of relatively large size wire is used

5. What is the displacement of the running and the starting windings used?

running winding displaces the starting winding by 180°

starting winding displaces the running winding by 180°

running winding displaces the starting winding by 90°

starting winding displaces the running winding by 90°

6. How is the winding arrangement and how is the conductors in each slot?

circular winding and same conductors in each slot

concentric winding and different conductor in each slot

circular winding and different conductor in each slot

concentric winding and same conductor in each slot

7. How much of the total slots are used for the reduction of the mmf wave harmonics?

80%

60%

65%

70%

8. What material is used in the tunnel of the rotor of the single phase induction motor?

steel

wood

aluminium

copper

9. What factors are used fixing the number of stator slots?

winding arrangement and number of poles

winding arrangement

winding arrangement or number of poles

number of poles

10. For what type of machines is the shaded pole starting method suitable?

for output above 50 watt

for output below 40 watt

for outputs below 60 watt

for output below 50 watt