Specifications

35
6. The electrical degree between adjacent slots for a 4 pole machine having 36 stator slots is
A) 10
0
B) 10
0
ε C) 20
0
D) 20
0
ε
7. The short pitch angle, á, of a 4 pole 3 phase winding ac machine wound with a coil span
of 140
0
ε is
A) 40
0
ε B) 180
0
ε C) 90
0
ε D) 60
0
ε
8. In three phase winding, three single phase windings are _____________ apart.
A) 180
0
ε B) 120
0
ε C) 90
0
ε D) 60
0
ε
9. If each pole of the same phase has unequal number of coils, then the winding is called as
A) balanced winding B) one slot winding C) unbalanced winding D) two slot winding
10. If the slots per pole per phase are equal to two, then the type of winding is called as
A) one slot winding B) balanced winding C) unbalanced winding D) two slot winding
Part - B
Answer the following questions in one or two words (1 Mark)
1. Name the two sides of a coil.
2. Write the formulae for the total number of conductors of a given machine.
3. When a coil is having a coil span equal to 180
0
ed
, what is it called as?
4. Name the two types of dc armature windings.
5. What is the angle between the three phase windings?
Part - C
Answer the following questions briefly (4 Marks)
1. With a neat diagram, write the functions of each part of a single turn coil.
2. What are called as whole coil windings?
3. What are called as half coil windings?
4. Determine the back and front pitches for a 4 pole lap winding with 24 slots.
5. Determine the back and front pitches for a 4 pole wave winding with 25 slots.
Part - D
Answer the following questions in two page level (20 Marks)
1. With a neat sketch, explain the different layers of insulation used in slots.
2. Draw simple lap and wave winding diagrams with different type of pitches marked in it.
3. Illustrate with neat diagrams, the placement of coils in a single layer and double layer windings
and the numbering of coil sides in each type of windings.
4. Derive expressions for electrical and mechanical degrees in terms of poles and slots.