FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A system and method of manufacturing induction motors.
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Jain Praveen Kumar of Crompton Greaves Ltd,, Machine (M7) Division, D-5, Industrial Area, MPAKVN, Mandideep - 462046, Madhya Pradesh, India, an Indian National.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
This invention relates to the field of motors.
Particularly, this invention relates to the field of induction motors.
Still particularly, this invention relates to a system and method of manufacturing induction motors.
BACKGROUND OF THE INVENTION:
An induction motor, typically, comprises a short circuit ring with axial grooves along its periphery, in which rotor bars are fitted and welded. The conventional process of manufacturing includes formation of grooves and MIG welding copper short circuit ring and rotor bar. This process of groove formation and welding is an additional process which may make the induction motor susceptible to damages and / or manufacturing defects.
Due to this additional process, the bars had to be bent during turning (groove formation process for MIG welding).
Generally, this groove formation resulted in distortion.
OBJECTS OF INVENTION:
An object of the invention is to provide to an improved system and method for manufacturing induction motor which eliminates additional process of bending of bars and reduces the manufacturing time.

Another object of the invention is to provide to an improved system and method for manufacturing induction motor which increases the strength of aluminum / copper bar and short circuit ring joint.
Yet another object of the invention is to provide to an improved system and method for manufacturing induction motor which increases aesthetics of the joints between short circuit ring and rotor bar.
Still another object of the invention is to provide to an improved system and method for manufacturing induction motor which reduces the cost due elimination of additional processes in manufacturing.
An additional object of the invention is to eliminate the process of groove formation and also to eliminate distortion of bars and ring which strengthens bond of aluminum/copper bar and short circuit ring.
Yet an additional object of the invention is to provide a defect -free system and method of manufacturing induction motor.
SUMMARY OF THE INVENTION:
According to this invention, there is provided a system for manufacturing
an improved induction motor, said system comprises:
a. a short circuit ring comprising a first hollow radial element and a second hollow radial element superimposed on said first radial element characterized in that, said second radial element having radially dispersed spokes of pre-defined breadth, each of said spokes having a U-shaped notch on its operative axial side; and

b. a rotor core cylinder adapted to be made from radially dispersed rotor bars, characterized in that, said rotor bars having a complementary reshaped notch adapted to fit with said U-shaped notch of said short circuit ring to provide a complementary fit of a plurality of rotor bars with a plurality of radially dispersed spokes of the ring to manufacture a complete induction motor without the process of groove formation or welding.
Typically, said slotted rotor bars are rectangular.
According to this invention, there is provided a method for manufacturing an improved induction motor, said method comprises the steps of:
a. providing a short circuit ring comprising a first hollow radial element
and a second hollow radial element superimposed on said first radial
element characterized in that, said second radial element having
radially dispersed spokes of pre-defined breadth, each of said spokes
having a U-shaped notch on its operative axial side;
b. providing a rotor core cylinder adapted to be made from radially
dispersed rotor bars, characterized in that, said rotor bars having a
complementary L-shaped notch adapted to fit with said U-shaped
notch of said short circuit ring; and
c. fitting of a plurality of rotor bars with a plurality of radially dispersed
spokes of the ring in its complementary configuration to manufacture
a complete induction motor without the process of groove formation
or welding.
Typically, said rotor bar is inserted to rotor core, and sorting of rotor bar from both the end with short ring to achieve a fit is performed.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates an exploded view of the induction motor which shows the short circuit ring and the rotor bars;
Figure 2 illustrates a close-up view of the short circuit ring of the induction motor;
Figure 3 illustrates a close-up view of the rotor bar of the induction motor;
Figure 4 illustrates an auxiliary view of the short circuit ring of the induction motor; and
Figure 5 illustrates an isometric view of the induction motor.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to the invention there is provided an improved system and method for manufacturing an induction motor comprising rotor having a slotted rotor bar and a short circuit ring.
Figure 1 illustrates an exploded view of the induction motor (100) which shows the short circuit ring and the rotor bars.

Figure 2 illustrates a close-up view of the short circuit ring of the induction motor.
Figure 3 illustrates a close-up view of the rotor bar of the induction motor.
Figure 4 illustrates an auxiliary view of the short circuit ring and rotor bar of the induction motor.
Figure 5 illustrates an isometric view of the induction motor.
In accordance with an embodiment of this invention, there is provided a short circuit ring (10), wherein said short circuit ring comprises a first hollow radial element (12) and a second hollow radial element (14) superimposed on said first radial element characterized in that, said second radial element has radially dispersed spokes (16) of pre-defined breadth, each of said spokes having a U-shaped notch (18) on its operative axial side.
In accordance with another embodiment of this invention, there is provided a rotor core cylinder (20) adapted to be made or radially dispersed rotor bars (22), characterized in that, said rotor bars having a complementary L-shaped notch (24) adapted to fit with said U-shaped notch of said short circuit ring.
This complementary fit of a plurality of rotor bars with a plurality of radially dispersed spokes of the ring provides a complete induction motor without the process of groove formation for welding.

Typically, said slotted rotor bar can have any shape, preferably rectangular.
According to this invention, there is provided a method of manufacturing an improved induction motor with said short circuit ring and said rotor bars wherein said rotor bar is inserted to rotor core, and sorting of rotor bar from both the end with short ring to achieve a fit is performed. The Joining / Coupling of rotor bar into short circuiting ring takes place with lesser processing time and improved quality of squirrel cage rotor.
In the prior art, process of groove formation results in failure of joints which is eliminated by current invention thereby making the present invention cost effective.

We claim:
1. A system for manufacturing an improved induction motor, said system
comprising:
a. a short circuit ring comprising a first hollow radial element and a
second hollow radial element superimposed on said first radial
element characterized in that, said second radial element having
radially dispersed spokes of pre-defined breadth, each of said spokes
having a U-shaped notch on its operative axial side; and
b. a rotor core cylinder adapted to be made from radially dispersed rotor
bars, characterized in that, said rotor bars having a complementary L-
shaped notch adapted to fit with said U-shaped notch of said short
circuit ring to provide a complementary fit of a plurality of rotor bars
With a plurality of radially dispersed spokes of the ring to manufacture
a complete induction motor without the process of groove formation
or welding.
2. A system as claimed in claim 1 wherein, said slotted rotor bars are rectangular.
3. A method for manufacturing an improved induction motor, said method comprising the steps of:
a. providing a short circuit ring comprising a first hollow radial element
and a second hollow radial element superimposed on said first radial
element characterized in that, said second radial element having
radially dispersed spokes of pre-defined breadth, each of said spokes
having a U-shaped notch on its operative axial side;
b. providing a rotor core cylinder adapted to be made from radially
4. A System as claimed in claim 3 wherein, said rotor bar is inserted to roter core, and sorting of rotor bar from both the end with short ring to achieve a fit is performed.