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
A modular brush gear assembly for electrical rotating machines
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Pandya Ankit and Upadhyay Amarendra; both of Crompton Greaves Limited, Machine (M7) Division, 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:
This invention relates to the field of motor assemblies.
Particularly, this invention relates to commutators and brushes of motors.
More particularly, this invention relates to a modular brush gear assembly for electrical rotating machines.
BACKGROUND OF THE INVENTION:
A motor is an electromechanical assembly which comprises stator, rotor, and commutator. While the stator is the stationary part of a rotor motor system, the rotor is the non-stationary part of a rotary motor.
A commutator is a rotary electrical switch in certain types of electric motors or electrical generators that periodically reverses the current direction between the rotor and the external circuit. A commutator is a common feature of a DC motor. This commutator consists of a number of segments of copper or of other suitable electrical conducting substance places together in the form of a ring with a sheet of electrical insulating substance between every two adjacent segments.
A commutator typically consists of a set of copper segments, fixed around part of the circumference of the rotating part of the machine (the rotor), and a set of spring-loaded brushes fixed to the stationary frame of the machine. The brushes are used to contact the surface of the commutator. An external source of current (for a motor) or electrical load (for a generator) is connected to the brushes.

The brushes are held by a brush gear assembly. DC motor transfers armature current through the brushes to the commutator. Depending upon the motor rating and current carrying capability, thereof, the brush size varies.
The brush gear assembly includes a plurality of pockets which serve as brush holders. As the brush size changes, these brush holders also need to have changed dimensions in order to allow for appropriate fitting of brushes in them.
There is a need for a modular brush holder, and a modular brush gear assembly thereof.
OBJECTS OF THE INVENTION:
An object of the invention is to provide modularity of fitment of brushes in a brush gear assembly.
Another object of the invention is to provide a gripped fitment of brushed in a brush gear assembly.
Yet another object of the invention is to allow a fitment of brushed gear assembly which can be changed according to size of brushes.
SUMMARY OF THE INVENTION:
According to this invention, there is provided a modular brush gear assembly for
motors having serially aligned box-slots for holding brushes, said assembly
comprising:
a plurality of contoured assemblies, each contoured assembly having a constant
outer peripheral dimension adapted to be in contact with said box-slots of said
brush gear assembly and further having different values of inner peripheral

dimensions which receive said brushes, the difference in said outer peripheral dimension and said inner peripheral dimension being the width of said contoured assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
According to this invention, there is also provided a rotating electrical machine with a modular brush gear assembly having serially aligned box-slots for holding brushes, said assembly comprising:
a plurality of contoured assemblies, each contoured assembly having a constant outer peripheral dimension adapted to be in contact with said box-slots of said brush gear assembly and further having different values of inner peripheral dimensions which receive said brushes, the difference in said outer peripheral dimension and said inner peripheral dimension being the width of said contoured assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
Typically, said inner peripheral dimensions correlate in dimensions to brush dimensions.
Typically, each of said contoured assemblies include lateral parallel walls joined width-wise by vertically extending walls to define a box-slot to receive a brush, with adjacent vertically extending walls being spaced apart, yet joined at their operative top, to conform to the space between two adjacent box slots of said brush gear assembly.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a brush gear assembly of the prior art.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 2 illustrates an isometric view of the contoured assembly adapted to be fitted in the brush holder segment of the brush gear assembly of Figure 1;
Figure 3 illustrates a front view of the contoured assembly adapted to be fitted in the brush holder segment of the brush gear assembly of Figure 1;
Figure 4 illustrates an isometric solid diagram view of the brush gear assembly with the contoured assembly of Figure 2 fitted in the brush gear assembly;
Figure 5 illustrates an isometric line diagram view of the brush gear assembly with the contoured assembly of Figure 2 fitted in the brush gear assembly; and
Figure 6 illustrates an isometric solid diagram of the brush gear assembly with the contoured assembly of Figure 2 fitted in the brush gear assembly along with brushes in the slots defined by the contoured assembly of Figure 2.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a brush gear assembly (100) of the prior art.
According to the prior art, there are provided box-slots (12) linearly aligned at one end of the brush gear assembly. Each of the box slots receives a brush which facilitates current transfer. As the motor rating varies, brush dimensions vary.

Here, the brush holding box-slots cannot be modified according to the brush dimensions. Thus, no modularity is available. The entire brush gear assembly needs to be replaced, according to the prior art, for varying brush dimensions.
According to this invention, there is provided a modular brush gear assembly for motors.
Figure 2 illustrates an isometric view of the contoured assembly (50) adapted to be fitted in the brush holder segment of the brush gear assembly of Figure 1.
Figure 3 illustrates a front view of the contoured assembly (50) adapted to be fitted in the brush holder segment of the brush gear assembly of Figure 1.
Figure 4 illustrates an isometric solid diagram view of the brush gear assembly (200) with the contoured assembly (50) of Figure 2 fitted in the brush gear assembly.
Figure 5 illustrates an isometric line diagram view of the brush gear assembly (200) with the contoured assembly (50) of Figure 2 fitted in the brush gear assembly.
Figure 6 illustrates an isometric solid diagram of the brush gear assembly (200) with the contoured assembly (50) of Figure 2 fitted in the brush gear assembly along with brushes (25) in the slots defined by the contoured assembly of Figure 2.
In accordance with an embodiment of this invention, there are provided a plurality of contoured assemblies (50), each contoured assembly having a constant outer peripheral dimension which is contact with the box-slots of the brush gear

assembly and further having different values of inner peripheral dimensions which receive the brushes. The difference in the outer peripheral dimension and the inner peripheral dimension is the width of the contoured assembly. Thus, variable inner peripheral dimensions account for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly. The inner peripheral dimensions are correlated to the brush dimensions.
Typically, the contoured assemblies include lateral parallel walls (52a, 52b) joined width-wise by vertically extending walls (54a, 54b) to define a box-slot (55). Adjacent vertically extending walls are spaced apart (56), yet joined at its operative top (58), to conform to the space between two adjacent box slots of the brush gear assembly.
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. A modular brush gear assembly for a rotating electrical machine having serially aligned box-slots for holding brushes, said assembly comprising: a plurality of contoured assemblies, each contoured assembly having a constant outer peripheral dimension adapted to be in contact with said box-slots of said brush gear assembly and further having different values of inner peripheral dimensions which receive said brushes, the difference in said outer peripheral dimension and said inner peripheral dimension being the width of said contoured assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
2. An assembly as claimed in claim 1 wherein, said inner peripheral dimensions correlate in dimensions to brush dimensions.
3. An assembly as claimed in claim 1 wherein, each of said contoured assemblies include lateral parallel walls joined width-wise by vertically extending walls to define a box-slot to receive a brush, with adjacent vertically extending walls being spaced apart, yet joined at their operative top, to conform to the space between two adjacent box slots of said brush gear assembly.
4. A rotating electrical machine with a modular brush gear assembly having serially aligned box-slots for holding brushes, said assembly comprising: a plurality of contoured assemblies, each contoured assembly having a constant outer peripheral dimension adapted to be in contact with said box-slots of said brush gear assembly and further having different values of inner

peripheral dimensions which receive said brushes, the difference in said outer peripheral dimension and said inner peripheral dimension being the width of said contoured assembly, thereby provisioning variable inner peripheral dimensions accounting for different breadths and hence, different box-slot dimensions for different contoured assemblies, correspondingly.
5. A rotating electrical machine as claimed in claim 4 wherein, said inner peripheral dimensions correlate in dimensions to brush dimensions.
6. A rotating electrical machine as claimed in claim 4 wherein, each of said contoured assemblies include lateral parallel walls joined width-wise by vertically extending walls to define a box-slot to receive a brush, with adjacent vertically extending walls being spaced apart, yet joined at their operative top, to conform to the space between two adjacent box slots of said brush gear assembly.