FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
An alignment guide tool for rotors.
APPLICANT
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company.
INVENTOR(S)
Qureshi Adil and Chatterjee Chayan; both of Crompton Greaves Limited, Machines (M7) Division, D-5, Industrial Area, MPAKVN, Mandideep- 462046, Madhya Pradesh, India; both Indian Nationals.
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:
The invention relates to the field of motors.
Particularly, this invention relates to an alignment guide tool for rotors.
BACKGROUND OF THE INVENTION:
An 'electrical rotating machine' or a 'rotating electrical machine' is any form of apparatus, equipment, or system which has a rotating member and generates, converts, transforms, or modifies electric power. These include apparatus such as a motor, generator, or synchronous converter.
Essentially all of the world's electric power is produced by rotating electrical generators, and about 70% of this energy is consumed in driving electric motors. Electric machines are electromechanical energy converters; generators convert mechanical energy into electrical energy and motors convert electrical energy into mechanical energy.
An electric machine can be constructed on the principle that a magnet will attract a piece of permeable magnetic material such as iron or magnetic steel. For example, a pole structure along with a magnetic block is allowed to rotate. The magnetic block will experience a torque tending to rotate it counterclockwise to the vertical direction.
One type of an 'electrical rotating machine' or a 'rotating electrical machine' is a motor. A motor for electrical purposes, i.e. an electric motor, is a device which converts electrical energy to mechanical energy. For industrial use, the ratings of

motor may typically be very high. They may be placed in housings or frames. It contains two main components; stator, rotor. The rotor is the non-stationary part of a rotary motor, which rotates because the wires and magnetic field of the motor are arranged so that a torque is developed about the rotor's axis. The stator is the stationary part of a rotor system. The rotor has a fanning action.
In these examples, if the rotor were allowed to move under the influence of the magnetic forces, it would eventually come to rest at an equilibrium position. Since most applications require continuous motion and constant torque, it is necessary to keep the angle between the rotor magnetic field and the stator magnetic field constant. Thus, in the above examples, the stator magnetic field must rotate ahead of the rotor.
A rotor includes two types of stampings; 1) core or central stampings which essentially form the central body of a rotor and 2) bunch of stacked end stampings which form the end portions of a rotor. A rotor essentially consists of a core assembly with rotor bars (12) and resistance rings (14) as shown in Figures 1 and 2 of the accompanying drawings. The rotor bars are brazed (assembled) to the resistance ring, which forms a shorted connection for all bars in the rotor.
The performance of an 'electrical rotating machine' or a 'rotating electrical machine' is defined by many characteristics. One such characteristic is its geometry of more specifically, the geometry of the rotor. These motors are subject to heavy vibrations throughout its lifespan for example high speed traction applications. The mismatched geometry also results in increased shaft voltage.

OBJECTS OF THE INVENTION:
An object of the invention is to provide a relatively accurate geometry of rotor.
Another object of the invention is to prevent incorrect dimensions after rotor brazing.
Yet another object of the invention is to provide a structurally stable rotor.
Still another object of the invention is to provide reduced copper content in brazed rotor bars.
An additional object of the invention is to facilitate vertical brazing of rotor bars in short circuit bring with rotor bars at equal height.
Another additional object of the invention is to provide uniformity in height of rotor bars.
SUMMARY OF THE INVENTION:
According to this invention, there is provided an alignment guide tool for a rotor, said tool being an annular rim with a top operative stepped surface with at least a step of said stepped surface in correlation to the height of rotor bar extending beyond a short circuit ring within which said rotor bars are to be brazed.
Typically, said guide tool comprises a top operative face, said top operative face being a substantially solid plate.
Typically, said stepped operative top surface is a two-stepped surface.

Typically, said stepped operative top surface is a two-stepped surface, with height of said first step being equal to the height of extension of said rotor bar beyond said ring.
Typically, operative bottom surface is a recessed surface so that it acts as a guide and aligns with a machine plate spigot.
Preferably, said stepped operative top surface is a two-stepped surface, with height of said first step being in the region of about 9.95 mm to 10.05 mm for a rotor bar extension height of about 10 mm.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a rotor;
Figure 2 illustrates an exploded view of a rotor;
Figure 3 illustrates a schematic isometric view of an alignment guide tool;
Figure 4a illustrates a front view of the alignment guide tool;
Figure 4b illustrates another front view of the alignment guide tool;
Figure 5 illustrates a schematic top view of the alignment guide tool;

Figure 6 illustrates a schematic isometric view of a rotor mounted on the alignment guide tool; and
Figure 7 illustrates a schematic front view of a rotor mounted on the alignment guide tool.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a rotor. Figure 2 illustrates an exploded view of a rotor.
A rotor (100) essentially consists of a core assembly with rotor bars (12) and resistance rings (14) as shown in Figures 1 and 2 of the accompanying drawings. The rotor bars are brazed (assembled) to the resistance ring, which forms a shorted connection for all bars in the rotor. The resistance rings are also known as short
circuit rings (SCR).
Copper bars (12) are inserted into rotor slots and short circuit ring (SCR) (14) is fitted with the bars. The ring (14) comprises slots, typically, rectangular slots disposed radially. These slots receive the rotor bars (12). The SCR and the bars are brazed to provide contact. Brazing of the joints is done keeping the rotor in vertical position. The clearance between the slots and bars is designed to be, typically, about 0.8mm. During brazing, if a stopper is provided, it would result to uneven bar height. Hence, there is a need for a guide tool in order to align the rotor bars, in-situation, to conduct the brazing of the rotor bars on the ring.
According to this invention, there is provided an alignment guide tool for a rotor.
Figure 3 illustrates a schematic isometric view of an alignment guide tool (200).

Figure 4a illustrates a front view of the alignment guide tool (200). Figure 4b illustrates another front view of the alignment guide tool (200).
Figure 5 illustrates a schematic top view of the alignment guide tool (200).
Figure 6 illustrates a schematic isometric view of a rotor mounted on the alignment guide tool.
Figure 7 illustrates a schematic front view of a rotor mounted on the alignment guide tool.
In accordance with an embodiment of this invention, there is provided an annular rim (200a) with a top operative stepped surface (200b). The top operative face is a substantially solid plate. The stepped operative top surface is a two-stepped surface (22, 24). The height of the first step (22) is equal to the height of the rotor bar (12) that extends beyond the ring (14).
The operative bottom surface (200c) is a recessed surface so that it acts as a guide and aligns with the machine plate spigot.
Typically, the rotor height beyond the short circuit ring is 10mm. Therefore, the first step height is in the region of 9.95 mm to 10.05 mm. In the tool, a limiting dimension is machined (9.95/10.05) so that alignment of bars and its positive movement is arrested.
The rotor bars rest on the annular are about the first step and are aligned to have the same height, during an operative vertical position. The bars are to be projected

10mm uniformly.
The technical advancement of this invention lies in providing a tool guide of vertical positioning of rotor bars in a ring such that height of the rotor bars extending through slots in the ring is uniformly maintained. Effective brazing can then be carried out. Incorrect dimensions are hence, arrested. Mismatched geometry resulting to increased shaft voltage is avoided. Also, there is reduced copper content (of rotor bar) if turning is done to match the misaligned brazed rotor bars
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. An alignment guide tool for a rotor, said tool being an annular rim with a top operative stepped surface with at least a step of said stepped surface in correlation to the height of rotor bar extending beyond a short circuit ring within which said rotor bars are to be brazed.
2. The alignment guide tool for a rotor as claimed in claim 1, wherein said guide tool comprising a top operative face, said top operative face being a substantially solid plate.
3. The alignment guide tool for a rotor as claimed in claim 1, wherein said stepped operative top surface being a two-stepped surface.
4. The alignment guide tool for a rotor as claimed in claim 1, wherein said stepped operative top surface being a two-stepped surface, with height of said first step being equal to the height of extension of said rotor bar beyond said ring.
5. The alignment guide tool for a rotor as claimed in claim 1, wherein operative bottom surface being a recessed surface so that it acts as a guide and aligns with a machine plate spigot.
6. The alignment guide tool for a rotor as claimed in claim 1, wherein said stepped operative top surface being a two-stepped surface, with height of

said first step being in the region of about 9.95 mm to 10.05 mm for a rotor bar extension height of about 10 mm.