Description:FIELD OF INVENTON
This invention relates to an electric motor. More particularly, this invention relates to novel constructional design of an electric motor and its components used for a submersible pump to improve the cooling of the electric motor.

BACKGROUD OF THE INVENTION
An electric motor is an electrical machine that converts electrical energy into mechanical energy in the form of rotational movement. Generally, an electric motor comprises a motor housing (shell), a stator mounted on an inner wall of the motor housing, and a rotor located at the centre of the stator. The stator comprises winding coils. The rotor comprises magnets and spins at high speeds, providing rotational mechanical energy to the system. The electric motor used for the submersible pump requires special construction, like shape and size. These motors have a cylindrical shape, a small diameter, and a long length due to the requirement for the insertion of the submersible pump in a bore-well. The submersible motor comprises a motor housing in the form of a cylindrical tube (shell), a stator attached to the inner diameter of the shell at a central location, end covers both ends of the shell and a rotor supported between the two end covers and located at the radially central position of the shell.

According to one prior art of submersible motors, the stators are concealed and filled with epoxy resin. The remaining volume of the shell of the submersible motor near the stator is filled with water. The water acts as a cooling and lubrication fluid inside the motor. Generally, resin-filled submersible motors are compact in size, and the length of the motor is significantly less as compared to conventional submersible motors. As the length of the motor is less, water volume inside the motor significantly reduces (for example, by 30%-40%). This results in motor cooling and lubrication issues. The thermal equilibrium temperature of this type of motor is higher as compared to conventional motors. Higher motor temperatures tend to motor failure due to overheating.

OBJECT OF THE INVENTION
The object of the invention is to solve the above mentioned problems of the submersible pump. More particularly, the object of the invention is to provide an electric motor for a submersible pump with resin filled stator and a cooling system that effectively cools the electric motor.

Another object of the invention is to design an electric motor for a submersible pump with resin filled stator which have more volume for water filling.

Another object of the invention is to design an electric motor for a submersible pump with resin filled stator which have more volume for water filling without increasing the overall diameter of the electric motor.

Another object of the invention is to design an electric motor for a submersible pump with resin filled stator which will not get heated during the operation and avoids failure of the same due to overheating.

SUMMARY OF INVENTION
To avoid the problems mentioned above and achieve the objects, according to one embodiment of the present invention, the applicant developed an electric motor for the submersible pump, wherein it comprises:
a) A motor shell,
b) A stator, which is attached to the motor shell from inside,
c) A rotor,
d) End Caps,
Wherein;
atleast an extension shell attached to at least one side of motor shell in the axial direction.

The extension shell 1 has internal threads at its one end, and the motor shell has corresponding external threads at its one end, the extension shell 1 is attached to the motor shell with the help of these threads.
The extension shell 2 has an internal diameter at its one end, and the motor shell has a corresponding external diameter at another end; the extension shell 2 is attached to the motor shell by a press fitting or interference fit with the help of these diameters.
A sealing ring is provided between the joint of the motor shell and the extension shell, the sealing ring selected from an '0' ring or a 'X' ring.
The axial length of extension shell is in the range of 50% to 80% of the length of the motor shell.
The stator of the motor is concealed by filling epoxy resin around it.
The end caps are attached to the extension shells with the help of known fastening arrangement.
Motor shell and extension shells are cylindrical in shape and of the same external diameter.
According to another embodiment of the present invention, both the extension shells have threads at its one end and attached to the motor shell, which has corresponding threads at both the ends.
According to another embodiment of the present invention, both the extension shells have machined diameter at its one end and attached to the motor shell, which has corresponding machined diameter, by a press fitting or interference fit with the help of these diameters.
According to another embodiment of the present invention, the diameter of extension shells is less than the diameter of the motor shell.
According to another embodiment of the present invention, the shape of the of extension shells and motor shell is different than cylindrical shape, like polygon shapes.

With the above arrangements, the water volume in the electric motor is significantly increased without increasing the overall diameter of the electric motor. Due to the increased volume of water, the electric motor can cooled effectively. Subsequently, the electric motor will not get heated during the operation, avoiding failure of the same due to overheating.

BRIEF DESCRIPTION OF DRAWINGS:

Figure 1 is a pictorial cross section side view of an electric motor of a submersible pump according to one prior art of the present invention.
Figure 2 is a pictorial cross section side view of an electric motor of a submersible pump according to one embodiment of the present invention.
Figure 3 is an exploded view of an electric motor of a submersible pump according to one embodiment of the present invention.
Figure 4 is a pictorial side view of an extension shell 1 of an electric motor of a submersible pump according to one embodiment of the present invention.
Figure 5 is a pictorial side view of an extension shell 2 of an electric motor of a submersible pump according to one embodiment of the present invention.
Figure 6 is a pictorial side view of a motor shell of an electric motor of a submersible pump according to one embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT:

Embodiments of present invention will now be explained with the help of figures herein below. All the aspects described herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope herein without departing from the spirit and scope thereof, and the present invention herein includes all such modifications.
Referring to Figure 1, according to one prior art of the present invention, an electric motor (1) of a submersible pump comprises; a motor shell (2), a stator (3), a rotor (4). The stator (3) is concealed by filling epoxy resin (5) in it. The remaining volume (6) of the shell of the submersible motor near the stator is filled with water. The water acts as a cooling and lubrication fluid inside the motor. Due to the size constrains of submersible pump and motor, the water volume (6) is very less. This results in motor (1) cooling and lubrication issues. The thermal equilibrium temperature of this type of motor (1) is higher as compared to conventional motors. Higher motor temperatures tend to motor failure due to overheating.
Referring to Figure 2 to 6, according to one embodiment of the present invention, an electric motor (11) of a submersible pump comprises; a motor shell (12), a stator (13), a rotor (14), end caps (15). The stator (13) is attached to the motor shell (12) from inside. The stator (13) of the motor (11) is concealed by filling epoxy resin (16) around it. In order to increase water volume (25) in the electric motor, extension shell 1 (17) and extension shell 2 (18) are attached to the motor shell (12) from two sides in the axial direction. The extension shell 1 (17) has internal threads (19) at its one end, and the motor shell (12) has corresponding external threads (20) at its one end. The extension shell 1 (17) is attached to the motor shell (12) with the help of these threads (19, 20).
The extension shell 2 (18) has a machined internal diameter (21) at its one end, and
the motor shell (12) has a corresponding machined external diameter (22) at another
end. The extension shell 2 (18) is attached to the motor shell (12) by a press fitting or interference fit at machined diameters (21, 22). A sealing ring (23) is provided between the joint of the motor shell (12) and the extension shell (17, 18). The sealing ring (23) may be an '0' ring or a 'X' ring. The extension shells' (17, 18) axial length may be in the range of 20% to 80% of the length of the motor shell (12). End caps (15) are attached to the extension shells (17, 18) with the help of standard fasteners like bolts (24). Motor shell (12) and extension shells (17, 18) are cylindrical in shape and of the same diameter.
With the above arrangements, the water volume (25) in the electric motor (11) is significantly increased without increasing the overall diameter of the electric motor (11) or submersible pump. Due to the increased volume of water (25), the electric motor (11) is cooled effectively. Subsequently, the electric motor (13) will not get heated during the operation, avoiding failure of the same due to overheating.
Although the invention has been described with regard to its embodiments, specific embodiments, and various examples, which constitute the best mode presently known to the inventors, it should be understood that various changes and modifications as would be obvious to one having the ordinary skill in this art may be made without departing from the scope of the invention. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole. All changes that come with meaning and range of equivalency of the claims are to be embraced within their scope.
, Claims:WE CLAIM:

Claim 1: An electric motor (11) for the submersible pump, wherein it comprises:
A motor shell (12),
A stator (13), which is attached to the motor shell (12) from inside,
A rotor (14),
End Caps (15),
Wherein;
atleast an extension shell (17, 18) attached to at least one side of motor shell (12) in the axial direction.

Claim 2: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; the extension shell 1 (17) has internal threads (19) at its one end, and the motor shell (12) has corresponding external threads (20) at its one end, the extension shell 1 (17) is attached to the motor shell (12) with the help of these threads (19, 20).

Claim 3: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; the extension shell 2 (18) has an internal diameter (21) at its one end, and the motor shell (12) has a corresponding external diameter (22) at another end; the extension shell 2 (18) is attached to the motor shell (12) by a press fitting or interference fit with the help of these diameters (21, 22).

Claim 4: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; a sealing ring (23) is provided between the joint of the motor shell (12) and the extension shell (17, 18); the sealing ring (23) selected from an '0' ring or a 'X' ring.

Claim 5: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; the axial length of extension shell (17, 18) is in the range of 50% to 80% of the length of the motor shell (12).

Claim 6: An electric motor (11) for the submersible pump as claimed in claim 1,
wherein; the stator (13) of the motor is concealed by filling epoxy resin (16) around it.
Claim 7: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; the end caps (15) are attached to the extension shells (17, 18) with the help of known fastening arrangement (24).

Claim 8: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; motor shell (12) and extension shells (17, 18) are cylindrical in shape and of the same external diameter.

Claim 9: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; both the extension shells (17, 18) have threads (19) at its one end and attached to the motor shell (12) , which has corresponding threads (20) at both the ends.

Claim 10: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; both the extension shells (17, 18) have machined diameter (21) at its one end and attached to the motor shell (12) , which has corresponding machined diameter (22) at both ends, by a press fitting or interference fit with the help of these diameters (21, 22).

Claim 11: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; the diameter of extension shells (17, 18) is less than the diameter of the motor shell (12).

Claim 12: An electric motor (11) for the submersible pump as claimed in claim 1, wherein; shape of the extension shells (17, 18) and motor shell (12) is different than cylindrical shape like polygon shapes.