GB2279183A

GB2279183A - Stator lamination design of single-phase induction motors

Info

Publication number: GB2279183A
Application number: GB9312608A
Authority: GB
Inventors: Chow Ying See
Original assignee: CAM MECHATRONIC
Current assignee: CAM MECHATRONIC
Priority date: 1993-06-18
Filing date: 1993-06-18
Publication date: 1994-12-21
Anticipated expiration: 2013-06-18
Also published as: GB2279183B; GB9312608D0

Abstract

A stator lamination for a single phase induction motor has slots containing only a main winding, slots containing only an auxiliary winding, and enlarged slots containing portions of both the main and auxiliary windings. To accommodate the large slots the lamination may be non-circular. <IMAGE>

Description

STATOR LAMINATION DESIGN OF SINGLE-PHASE INDUCTION MOTORS A new stator lamination design of single-phase induction motors is presented in this invention. The area of the slots in which both of the main winding and auxiliary winding are located is larger than the others.

The lamination design has a significant effect on the performance of single-phase induction motors in particular on the iron losses, magnetizing current and efficiency.

Fig.l shows a conventional 2-pole single-phase induction motor's lamination. There are twenty four slots in the stator. Two stator windings, one of them is the main winding and the other is the auxiliary winding, are located in these slots. Slots 1,2,11,12,13,14,23 and 24 are occupied by the main winding alone.

Slots 5,6,7,8,17,18,19 and 20 are occupied by the auxiliary winding alone. Slots 3,4,9,10,15,16,21 and 22 are occupied by both the main winding and auxiliary winding. The shaded area in slots indicates the area occupied by the auxiliary winding. The wire diameter of the main winding is 0.9 mm and the wire diameter of the auxiliary winding is 0.5 mm. Table 1 gives the turn number.of the main winding and the auxiliary winding in each slot. The total wire area in a slot, the product of the conductor number in the slot multiplied by the wire area, including both the main winding and auxiliary winding, is also given in Table 1. Since the total wire area in the slots occupied by the auxiliary winding alone, such as slots 5,6,7,8,17,18,19 and 20, is much smaller than the total wire area in the other slots, the area of slots in which only auxiliary winding is located is made smaller as shown in Fig.l.

However, in a single-phase induction motor with new winding design the product of the total turn number multiplied by the wire area of the main winding is close to the product of the total turn number multiplied by the wire area of the auxiliary winding. Table 2 gives the turn number and the total wire area in a slot, the product of the conductor number in the slot multiplied by the wire area, including both the main winding and the auxiliary winding in the slot. The wire diameter of the main winding is 0.7 mm. The wire diameter of the auxiliary winding is 0.74 mm. It can be seen that the total wire area in the slots in which only main winding is located is nearly equal to the total wire area in the slots in which only auxiliary winding is located. But the total wire area in the slots in which both the main winding and the auxiliary winding are located is much greater.

A new lamination design as shown in Fig.2 is presented in this invention to fit the new winding design given in Table 2. In Fig.2 the slots housing both the main winding and auxiliary winding are enlarged. At the same time the configuration of the stator lamination is changed to a non-circular one to avoid too high flux density in the yoke behind those enlarged slots and to avoid resulting in high iron losses and low efficiency. It must be noted that the lamination with the enlarged yoke does not increase the material cost, since the material needed for the lamination in Fig.2 is the same as that in Fig.l, i.e the square of the diameter of the lamination in Fig.l.

Since the lamination is no longer circular, it is difficult to use a circular frame to house the lamination. A new structure is presented in Fig.3. The frame is omitted. The two end covers are directly mounted on the stator lamination. The shape of the end covers are made the same as the lamination as shown in Fig.4.

The four arcs (1,2,3 and 4) of the end covers are machined to fit the arcs (1',2',3' and 4') of the lamination in Fig.3. Table 1

Slot 0 1 2 3 4 1 5 6 No of turn of 106 106 84 80 0 0 main winding No of turn of 0 0 72 76 84 84 auxiliary Total wire area 67.43 67.43 67.58 65.81 16.49 16.49 including main and auxiliary winding mm2 Slot 7 8 9 10 11 12 No of turn of 0 0 80 84 106 106 main winding No of turn of 84 84 76 72 0 0 auxiliary Total wire area 16.49 16.49 65.81 67.58 67.43 67.43 including main and auxiliary winding mm Slot 13 14 15 16 17 18 No of turn of 106 106 84 80 0 0 main winding No of turn of 0 0 72 76 84 84 auxiliary Total wire area 67.43 67.43 67.58 65.81 16.49 16.49 including amin and auxiliary winding mm Slot 19 20 21 22 23 24 No of turn of 0 0 80 84 106 106 main winding No of turn of 84 84 76 72 0 0 auxiliary Total wire area 16.49 16.49 65.81 67.58 67.43 67.43 including main and auxiliary winding mm Table 2

Slot 1 2 3 4 5 6 No of turn of 106 106 84 80 0 0 main winding No of turn of 0 0 72 75 95 95 auxiliary Total wire area 40.79 40.79 63.34 63.05 40.86 40.86 including main and auxiliary winding mm Slot 7 8 9 10 11 12 No of turn of 0 0 80 84 106 106 main winding No of turn of 95 95 75 72 0 0 auxiliary Total wire area 40.86 40.86 63.05 63.34 40.79 40.79 including main and auxiliary winding mm Slot 13 14 | 15 16 1 17 18 No of turn of 106 106 84 80 0 0 main winding No of turn of 0 0 72 75 95 95 auxiliary Total wire area 40.79 40.79 63.34 63.05 | 40.86 40.86 including main and auxiliary winding mm Slot 19 20 21 22 1 23 24 No of turn of 0 0 80 84 106 106 || main winding No of turn of 95 95 75 72 0 0 auxiliary Total wire area 40.86 40.86 63.05 63.34 40.79 40.79 including main and auxiliary winding mm

Claims

CLAIMS 1. A stator lamination design for single-phase induction motors, the lamination design comprising the enlarged area of slots in which both the main winding and auxiliary winding are located.

The lamination is still a circular one.
2. A stator lamination design for single-phase induction motors according to claim 1, wherein the lamination is no longer a circular one. The yoke behind these enlarged slots is enlarged as shown in Fig.2.
3. A stator lamination design for single-phase induction motors according to claim 1, a new structure is presented. The frame is omitted. The two end covers are directly mounted on the lamination. The shape of the end covers are made the same as the lamination. The four arcs of the end covers are machined to fit the four arcs of the lamination.