1. Government Engineering College, Valsad
Subject :- Elements Of Electrical Design

2. Submitted to :- J.B.patel Sir
Group : - 11
SR NO.
ENROLL NO.
NAME 1
JIVANI DHRUPAL 2
JOSHI GOPAL 3
THAKOR JIGAR 4
MALAVIYA CHARVIN
Submitted to :- J.B.patel Sir

3. Concentric winding

4. Introduction :
Three-phase concentric winding consists of coil groups laid in the slots so that all the coils of each group are concentric.
That is, the coil with the smallest slot pitch is surrounding by the coil with the next larger slot pitch and so on to make up a coil group.
Each coil consists of several turns and the cross-over from one coil to the next is indicated by a short slanted line (jumper).

5. Types of AC armature winding ;
Concentrated armature winding;
Single layer winding
Double layer winding
Concentric winding
Mush winding
Lap winding
Wave winding
Hemitro-pic
Whole coil winding
Integral slot
Fraction-al slot
Integral slot
Fraction-al slot

6. Concentrated armature winding ;
Concentrated winding is employed where number of slots on the armature is equal to number of poles in the machine.
This armature winding of alternator gives maximum output voltage but not exactly sinusoidal.
Here, number poles = number of slots = number of coil sides , which is shown in below fig.
Here, one coil side is inside one slot under one pole and other coil side inside other slot under next pole.

8. Construction of concentrated winding ;
In order to construct the diagram for a winding, the following data must be known:
S - The number of slots in the stator
P – The number of poles
m – The number of phases
YS – The pitch of the winding
a – The number of parallel circuits in the windings

9. The pitch of the winding is determined by the formula
The pitch is the distance between two sides of a coil expressed as the difference between the numbers of the slots in which the sides lie.
Another important value of the winding of ac machines is the number of slot per phase per pole denoted by the letter q. It can be determined by the formula

10. Example#1: on concentric winding
Given data
S=24; p=4;m=3; a=1; type=Concentric
Solution
The number of coil groups, K
The number of slots per pole per phase, q
Coil pitch
The shorter coil pitch = YS-1=6-1=5
i.e. there is two coil groups per phase
i.e. there are two coils in a group
Full-Pitch ( average pitch)

11. The larger coil pitch = YS+1=6+1=7
The electrical angle, 
The angle between adjacent slots, 
The distance between the beginning of each phase, 
If the beginning of Phase A is slot 1, then the beginning of phase B is slot 1+=5 and the beginning of phase C is slot 1+2=1+8=9

12. PROCEDURE FOR CONSTRUCTING OF CONCENTRIC WINDINGS
Data: S= 24, P = 4, a = 1, q = 2, K = 6

13. Coil Groups of Phase A
The first and second slots will be occupied by left-hand sides of the first coil group of phase A.
Leave four, or 2q slots free for other two phases occupy slots 7 & 8 with the right hand side of the first coil group.
Next to it will lie a second coil group of the same size which occupies slots 9,10,15,16.

14. Coil Groups of Phase B
In order to find, where the second phase (B) should begin, it is necessary to know the angle between slots in electrical degrees.
=180.P = = 7200 – Electrical degree
The angle between adjacent slots, 
The distance between phase beginnings will have

15. Coil Groups of Phase C

16. Current direction N
1-6 S
7-12 N
13-18 S
19-24

17. Phase A – Coil groups interconnection

18. Phase B – Coil groups interconnection

19. Phase C – Coil groups interconnection

20. Terminals

21. THANK YOU