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
AN EFFICIENT UNIFORM COOLING SYSTEM FOR A MOTOR.
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTORS
Manoharan Mahendran, Pawar Sumedh, Paramane Sachin, Joshi Kishor Uddhav and Dhavileswarapu Shrinivas of Crompton Greaves Ltd, Analytics Department, Global R&D Centre, Crompton Greaves Ltd, Kanjurmarg (East), Mumbai 400042, Maharashtra, India; all 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 cooling systems for motors.
Particularly, this invention envisages an efficient uniform cooling system for a motor.
Background of the Invention:
Motors are heat generating mechanical assemblies. Due to the power it generates, heat output is a byproduct of the motor mechanism. For efficient working of motors, it is imperative that this byproduct of heat does not increase beyond defined thresholds. Hence, a ventilating or cooling system for such motors is necessary.
Typically, air from a motor is guided to a heat exchanger through this cooling mechanism. The air that enters the heat exchanger should thus be forward guided i.e. without backflow or any vortex formation, should also have a constant pressure gradient in its flow, and also be sufficiently cooled in the amount of time which takes for its transfer, within the given space.
Prior art:
Presently, a motor with baffles are provided across the length of the guided duct. These baffles are curved plates which guide the air flow from its lateral entry position to its axial exit position. Thus, the air flow undergoes a phase shift of about 90 degrees. The baffles, as mentioned, are plates which substantially cover the breadth of the duct, and hence, results in more weight. The air flow from the motor fan is guided by these baffles and causes recirculation of air near it. This action results in resistance to the air flow and causes backflow of air and thereby causes pressure drop. This may also lead to vortex formation, if the air guidance is not linear. Moreover, as the entry of air to the heat exchanger is not smooth, it increases the noise level and vibration of the motor.
Objects of the Invention:
An object of the invention is to provide efficient cooling of a motor and its associated assemblies.

Another object of the invention is to provide a guided airflow through a cooling system.
Yet another object of the invention is to reduce noise level and vibration of motor caused due to inappropriate airflow.
Still another object of the invention is to provide airflow through cooling system without backflow or vortex formation.
Summary of the Invention:
According to this invention, there is provided an efficient cooling system for motors, said cooling system comprises:
a. air entry means adapted to facilitate entry of air into said cooling
system;
b. air exit means adapted to facilitate exit of air from said cooling
system; and
c. plurality of curvilinear (baffle) strips adapted to guide air from said air
entry means to said air exit means, characterized in that, a pair of
laterally dispersed curvilinear strips form a first set of baffle strips for
causing phase of shift in air flow of about 90 degrees from said air
entry means to said air exit means.
Typically, a pair of laterally dispersed curvilinear strips below said first set of baffle strips forms a second set of baffle strips.
Particularly, said baffle strips are located at a distance of about 100 mm from the base.
Alternatively, said baffle strips are thrice in size of the boundary level thickness of said cooling system.

Brief Description of the Accompanying Drawings:
Figures la and lb illustrate a side view of the cooling system for motor in accordance with the prior art; and
Figure 2 illustrates a front view of the cooling system for motor in accordance with the prior art.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 3 illustrates an auxiliary view and Figure 4 illustrates a front view of the cooling system.
Figure 5 illustrates a side view of the cooling system along with its adjunct mechanisms i.e. motor and heat exchanger.
Figure 6a illustrates CFD analysis of cooling system (of prior art) of Figure 1. Figure 6b illustrates CFD analysis of cooling system (in accordance with this invention) of Figure 3.
Detailed Description of the Accompanying Drawings:
Figures la and lb illustrate a side view of the cooling system (100) for motor in accordance with the prior art; and
Figure 2 illustrates a front view of the cooling system (100) for motor in accordance with the prior art.
Here, baffle means (110, 120) are provided in its curvilinear position so as to guide air (as shown by the dotted arrow lines). Typically, the baffle means provided herein are baffle plates which cover the entire breadth of the cooling system. It was observed that the baffle means is

According to this invention, there is provided an efficient uniform cooling system for motor.
Figure 3 illustrates an auxiliary view and Figure 4 illustrates a front view of the cooling system (200) according to this invention.
Figure 5 illustrates a side view of the cooling system along with its adjunct mechanisms i.e. motor (205) and heat exchanger (215). A fan (225) facilitates entry of air into the cooling system.
In accordance with an embodiment of this invention, there is provided an air entry means (210) adapted to facilitate entry of air into said cooling system,
In accordance with another embodiment of this invention, there is provided an air exit means (220) adapted to facilitate exit of air from said cooling system.
In accordance with yet another embodiment of this invention, there is provided a plurality of curvilinear (baffle) strips (230, 240, 250, 260) adapted to guide air from said air entry means to said air exit means. Typically, two pair of laterally disposed curvilinear strips, one below the other, are used to cause the phase of shift of about 90 degrees from said air entry means to said air exit means. Typically, said baffle strips are fences which are provided in the flow passage of the motor. Its shape and size is used to guide the air flow. It allows smooth entry of air to the heat exchanger tubes, which are associated with the exit means and thus uniformly distributes air to enter the heat exchanger tubes, causes lesser back pressure, better air flow distribution, less pressure drop, reduced noise of fan and vibrations of motor. This improves thermal performance of the motor by improving air flow distribution, reduced pressure drop and thereby enhancing heat dissipation. The shape and size of fence i.e. the baffle strips also help in reducing weight of motor. The shape of the fence typically depends on the angular turning direction.

Presently, it is necessary that for better heat dissipation from the heat exchanger tubes air should enter uniformly with reduced pressure drop. Better air flow distribution of air can be achieved by providing a smoother entry of the air through the aerodynamic shape of fence which is provided due to its curvilinear design. This aerodynamic fence provides the guided path for air flow and eliminates the recirculation of air compared to prior art and air flow distribution becomes uniform. Furthermore, as smoother entry of air is provided by fence it causes reduced pressure drop which results in decrease in fan power consumption. Moreover, smoother entry reduces the fan noise. Aerodynamic fence improve air flow distribution and thereby increases heat dissipation. Due to this, modification, weight of motor can be reduced which, in turn, will help to reduce the cost of motor.
Aerodynamic baffle strip (fence) designed according to the flow path of air provides the smooth entry of air in the heat exchanger tubes. Moreover, it avoids the back flow and recirculation of air at the fence. The aerodynamic profile of fences provides appropriate guidance to the air flow. It reduces pressure drop and allows better air flow distribution thereby cooling the motor more effectively.
This cooling system is applicable for entire range of motors where forced air cooling is used. Arrow lines of Figure 5 illustrate the direction of air flow through the cooling system of this invention, through the fan, motor, and through the heat exchanger.
These effects are studied in a better way by CFD analysis as seen in Figures 6a and 6b of the accompanying drawings. Figure 6a illustrates CFD analysis of cooling system (of prior art) of Figure 1. Figure 6b illustrates CFD analysis of cooling system (in accordance with this invention) of Figure 3.
The CFD analysis diagram shows uniform air flow cooling of the cooling system of the current invention as opposed to the prior art.

We claim,
1. An efficient cooling system for motors, said cooling system comprising:
a. air entry means adapted to facilitate entry of air into said cooling
system;
b. air exit means adapted to facilitate exit of air from said cooling
system; and
c. plurality of curvilinear (baffle) strips adapted to guide air from said
air entry means to said air exit means, characterized in that, a pair
of laterally dispersed curvilinear strips form a first set of baffle
strips for causing phase of shift in air flow of about 90 degrees
from said air entry means to said air exit means.
2. A system as claimed in claim 1 wherein, a pair of laterally dispersed curvilinear strips below said first set of baffle strips forms a second set of baffle strips.
3. A system as claimed in claim 1 wherein, said baffle strips are located at a distance of about 100 mm from the base.
4. A system as claimed in claim 1 wherein, said baffle strips are thrice in size of the boundary level thickness of said cooling system.