FIELD OF THE INVENTION
The present invention generally relates to electrical machines and in particular to a method of producing the stator core of an electrical machine. More particularly, the invention relates to a .method of producing a stator core of a high capacity electrical machine having multi-turn concentrated windings. The invention further relates to a process of easy assembly of a stator core and winding of high capacity electrical machines having multi-turn concentrated windings.
BACKGROUND OF THE INVENTION
In the recent developments of electrical machines, a concentrated winding is widely used as it has several advantages compared to the distributed winding. Admittedly the harmonic components produced in the case of distributed winding are low compared to those produced in the concentrated winding. A concentrated winding is required in many applications such as low-speed machines, motors with wide constant power speed range, machines with high fault tolerant capability, machines with reduced size and increased efficiency etc., While the manufacturing of low capacity electrical machines with multi turn concentrated windings is easy because of utilization of thin conductors, the manufacturing of high capacity electrical machines with multi turn concentrated windings is difficult as the placement of winding in the stator core in this case is a cumbersome process because of utilization of thick copper bars.
In DE102013214128 patent, a stator assembly of an electrical machine with concentrated winding is proposed where in the assembly procedure of a stator core and the winding of an electrical machine is found to be a cumbersome procedure.

OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a method of producing the stator core of a high capacity electrical machine having multi-turn concentrated windings.
Another object of the invention is to propose a method of producing the stator core of a high capacity electrical machine having multi turn concentrated windings, which allows an assembly of the stator core and the winding of the high capacity electrical machine having multi-turn concentrated windings.
SUMMARY OF THE INVENTION
According to the invention, there is provided a method of producing a stator core of a high capacity electrical machine having multi turn concentrated windings. The invention additionally provides an easy assembly of the winding and stator core.
As per the invention, the laminations of the stator core and the laminations of stator pole shoe are made separately and press fitted to form a new stator core, stator pole shoe and of an electrical machine shown in Fig. 1.
The stator pole shoe is significant in that the width of the pole shoe above and below the rectangular grooves as shown in Fig. 1 must remain same for better placement of concentrated winding as shown in Fig. 2 and Fig. 3.
The stator core is significant in that it is having a plurality of slots with slot profile as shown in Fig. 1 which accommodate part of the stator pole shoes into them as shown in Fig. 4 and Fig. 5.

The stator pole shoe is also significant in that the part of the pole shoe is having a body profile with rectangular grooves as shown in Fig. 1, such that the part exactly fits into the slot provided in the stator core as shown in Fig. 4 and Fig. 5.
The assembly of the stator core and winding of the high capacity electrical machine having multi turn concentrated windings is also significant in that the insertion of the stator pole shoe along with the concentrated winding over it into the stator core becomes easy because of gravity if it is carried out by keeping the stator core of an electrical machine in the vertical position.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings, in which:
Fig. 1 is a view of 3D model of stator core, winding and pole shoe of stator of an electrical machine.
Fig. 2 and Fig. 3 are views of 3D models of stator core assembly where in the winding is placed onto the pole shoe of stator.
Fig. 4 and Fig. 5 and Fig. 6 are views of 3D models of stator core assembly where in the stator pole shoe along with the winding is inserted into the stator core.

DETAILED DESCRIPTION OF THE INVENTION
In the present invention, a method of producing a stator core capable of being easily assembled to the winding of a high capacity electrical machine having multi turn concentrated windings is proposed in order to exploit the advantages of concentrated windings compared to those of distributed winding in the case of high capacity electrical machines also.
According to the invention, the stator core and the stator pole shoes as shown in Fig. 1, are produced by making the laminations of the stator core and the laminations of stator pole shoe separately and press fitted in order to have an easy assembly of the winding and stator core of the electrical machine.
The stator pole shoe is significant in that the width of the pole shoe above and below the rectangular grooves as shown in Fig. 1, is maintained at an identical value for better placement of concentrated winding as shown in Fig. 2 and Fig. 3. The concentrated winding shown in Fig. 1 need not be of rectangular type winding but can also be of any other type like diamond shaped winding etc.,
The stator core comprises a plurality of a slots with a slot profile as shown in Fig. 1 which accommodate the part of stator pole shoes into them as shown in Fig. 4 and Fig. 5. The slots provided in the stator core in the exemplary embodiment are of rectangular type with intermediate rectangular protrusions as shown in Fig. 1, to hold the pole shoe. These protrusions need not necessarily be rectangular in shape but can be of any other shape which can hold the pole shoe but the constraint is that the part of the pole shoe must have a corresponding body profile to accommodate it into the slot of the stator core.

The slot profile can be finalized after carrying out the structural analysis in order to
reduce the stress concentration factors at critical points in the stator core based on
the weight of the pole shoe and the amount of the copper used in the
concentrated winding.
The part of the stator pole shoe is having a body profile with rectangular grooves as shown in Fig. 1, such that the part exactly fits into the slot provided in the stator core as shown in Fig. 4 and Fig. 5. The grooves provided in the pole shoe need not be rectangular and the shape of the grooves depend on the slot profile used in the stator core. For instance, if the protrusions in the slots of the stator core are circular then the grooves in the stator pole shoes will also be circular.
The assembly of the stator core and winding of the high capacity electrical machine having multi turn concentrated windings is also significant in that the insertion of stator pole shoe along with the concentrated winding over it into the stator core of the electrical machine becomes easy because of gravity, when carried out by placing the stator core in the vertical position.

WE CLAIM :
1. A method of producing the stator core of a high capacity electrical
machine having multi turn concentrated windings, comprising the steps of:-
producing separately the laminations of the stator core and the lamination of the stator pole shoes; and press-fitting the laminations of both types to achieve an easy assembly.
2. The method as claimed in claim 1, wherein a portion of the stator pole shoes has a body profile with a plurality of rectangular grooves.
3. The method as claimed in claim 1 or 2, wherein a plurality of stator pole shoes are placed above and below the rectangular grooves for easy placement of the concentrated windings.
4. The method as claimed in claim 3, wherein the width of the plurality of stator pole shoes is identical.
5. The method as claimed in claim 1, wherein the stator core comprises a plurality of slots with compensatory profile of the part of the stator pole shoes.
6. The method as claimed in claim 5, wherein the plurality of slots on the stator core are provided with multiple intermediate protrusion in a spaced apart manner.

7. The method as claimed in any of the preceding claims, wherein the shape
of the slots, protrusions, and grooves can be of any possible shape but with matching geometry to each other.