Claims:We Claim:
1. A line/self-starting permanent magnet submersible electric motor, wherein motor comprises;

a stator (12) having a laminated core made of stacked sheet metal laminations, or of a continuous edge wound metal tape, equipped with a 3-phase winding(11) which is laid down in the stator (12) core over its entire length,

a rotor assembly being rotatably mounted concentrically with respect to the stator (12),

a sand guard (1) mounted on the top of the stator (12), a radial shaft (8) mounted with the sand guard (1) at the top of the stator (12), inside the stator (12) a cable gland (9) being fixed, an upper motor bearing bush (10) being placed with rotor shaft (16) of the rotor assembly, an upper housing (2) is attached with the middle of a rotor shaft (16) of the rotor assembly, a thrust bearing plate (5) and thrust bearing ring (14) are attached through a thrust bearing housing (6) with a lower motor bearing bush (13) at the end of the rotor shaft (16) of the rotor assembly, a breather diaphragm (7) and a drain plug (15) being placed at the end of the stator body (12),

Characterized in that,

the rotor assembly having a rotor shaft (1) with combination of plurality of permanent magnets (18) and plurality of conductors (20) with the discrete conductive bars being stamped through stamping (19) inside the stator body (12).

2. The line/self-starting permanent magnet submersible electric motor as claimed in claim 1, wherein the plurality of permanent magnets (18) being located radially inwards from the plurality of conductors (20).

3. The line/self-starting permanent magnet submersible electric motor as claimed in claim 1, wherein the plurality of conductors (20) being provided by plurality of discrete conductive bars.

4. The line/self-starting permanent magnet submersible electric motor as claimed in claim 3, wherein a plurality of discrete conductive bars that extend between a pair of end balance rings (24) and arranged substantially symmetrically around the rotor body.

5. The line/self-starting permanent magnet submersible electric motor as claimed in claim 4, wherein the shape of the discrete conductive bars of the rotor assembly are round, pear, oval, oblong, elliptical, square, rectangle, triangle, equilateral polygon, equiangular polygon, regular polygon or irregular polygon.

6. The line/self-starting permanent magnet submersible electric motor as claimed in claim 5, wherein shape of the plurality of permanent magnets(18) is arc shape, semi hexagon profile, semi octagon profile, semi decagon profile or semi polygon profile.

7. The line/self-starting permanent magnet submersible electric motor as claimed in claim 6, wherein the plurality of permanent magnets (18) being arranged outward of radially of the rotor shaft (1).

8. The line/self-starting permanent magnet submersible electric motor as claimed in claim 4, wherein the plurality of conductors (20) being arranged inward of radially of the stator body (12).

9. The line/self-starting permanent magnet submersible electric motor as claimed in claim 1, wherein the plurality of conductors(20) placed with end copper plate (22) with appropriate brazing process or injection molding of the conducting material.

10. The line/self-starting permanent magnet submersible electric motor as claimed in claim 1, wherein the plurality of permanent magnets (18) and plurality of conductors (20) located in slot, cleated or dovetailed section being formed on the outer surface of the rotor body.

Dated this on 25th May, 2020.
, Description:
FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION: LINE/SELF STARTING PERMANENT MAGNET SUBMERSIBLE ELECTRIC MOTOR

2. APPLICANT:

(a) NAME : Duke Plasto Technique Pvt. Ltd.
(b) NATIONALITY: Indian
(c) ADDRESS : N. H. 27, Deesa Highway,
Badarpura,
Palanpur – 385510,
Gujarat, India
PREAMBLE TO THE DESCRIPTION

PROVISIONAL

The following specification describes the invention.
þ COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THEINVENTION
[0001] The invention relates to a submersible electric motor and more particularly it relates to a line/Self Starting Permanent Magnet Submersible Electric Motor having a combination of squirrel cage induction submersible electric motor configuration and permanent magnet electric submersible motor configuration which avoid electronics controller or drive for starting and running in operation and reduce the cost of system and reduce of complexity of operation and system.
BACKGROUND OF THE INVENTION
[0002] The Permanent magnet electric motors as present scenario are typically unable to operate without appropriate controller or electronics controller because they cannot be started without control power on line. The permanent magnet electric motors have a controller which is working close loop and open loop. In particularly close loop electronic/drive required signal of rotor position through transducer and control electronics to run an electric motor. In Particularly Submersible electric motor working with very long cable up to 1000 Meter and above. So permanent magnet motor require motor component like inductor or any electronic (That is add more cost of the system.) For reduce a harmonic loss due to back e.m.f. harmonic loss (Line Capacitor) that effects on cable life and sometime mismatch the communication in between motor and controller this types of drawback are present in permanent magnet submersible motor. [Here, Inductor loss is around 3% and Drive Loss is around 3% (Approximate value)].
[0003] The Patent Number US3935487 A disclosure relates to a permanent magnet motor which generates mechanical output power by the repulsion forces between a movable permanent magnet and a fixed permanent magnet. A movable magnetic shield is interposed between the magnets when they are adjacent one another and then the shield is moved to expose the fixed magnet as the movable magnet passes by. A second fixed magnet can be added to increase the output power by attracting the movable magnet as it approaches. The movable magnetic shield is interposed between the movable magnet and the second fixed magnet when they are adjacent one another.
[0004] The Squirrel cage induction submersible electric motor is very popular and practical. In the present scenario to operate on line with grid direct power without any electronics and controller starting is very smooth in operation but as on day efficiency factor are competitively poor with compare to permanent magnet electric motor. But in current situation of IE3 IE4 and IE5 efficiency is far more than current efficiency achieved in squirrel cage induction submersible electric motor. Squirrel cage induction submersible electric motor have drawback of its lesser efficiency in compare to the permanent magnet electric motor.
[0005] The Patent Number US2004012293 (A1) disclosure relates to the field of dynamoelectric machines and is applicable for the constructive configuration of the rotor of an asynchronous induction motor which has windings configured as conductor bars and short-circuited by end rings. A squirrel-cage rotor configured in this manner is characterized by a cage having in radial direction a small structural height. As a consequence, the rotor shaft can have a greater diameter, when compared to rotors that have a same outer diameter and a short-circuit cage of greater structural height, so that a stiffer rotor construction and thus less tendency to vibrate at high rotation speeds is realized. As the conductor bars are arranged flush with the surface of the rotor-for example, by applying a material-removing process-the squirrel-cage rotor has a smooth surface and thus very small friction losses. The soldering process, required to secure the conductor bars in the slots of the rotor core, can easily be implemented. In order to introduce solder into the joint area, it is recommended to provide the conductor bars with an elongate channel in the area confronting the slot base for introducing the solder material before the conductor bars are placed into the slots. The channel may have a circular configuration for receiving a round solder wire. As an alternative, the rod-shaped or wire-shaped solder material may initially be placed into the respective slot, and subsequently the conductor bar with the channel are put over the solder material.
[0006] Therefore, a need exists for a motor that is capable to overcome the limitations of permanent magnet electric motor and squirrel cage induction submersible electric motor.
OBJECT OF THE INVENTION
[0007] The main object of the present invention is to provide Line/self-starting permanent magnet submersible electric motor that is capable of self –starting when operated directly on-line.
[0008] Another object of the invention is to provide direct smooth starting with ordinary low cost simple star & star delta starter.
[0009] Yet another object of the invention is to run the motor at low starting current.
[0010] Yet another object of the invention is to increase the efficiency of the motor for significant energy saving.
[0011] Yet another object of the invention is to overcome the power losses and rotor losses into the motor.
[0012] Yet another object of the invention is to overcome the problem of the cable length.
[0013] Yet another object of the invention is to provide higher power density.
[0014] Yet another object of the invention is to provide good power factor then squirrel cage induction submersible electric motor.
[0015] These and other objects will be apparent based on the disclosure herein.
SUMMARY OF THE INVENTION
[0016] The present invention relates a submersible electric motor and more particularly it relates to a line/self-starting permanent magnet submersible electric motor having a combination of squirrel cage induction submersible electric motor and permanent magnet electric submersible motor which avoid electronics controller or drive for starting and running in operation reduce the cost of system and reduce of complexity of operation and system. The line/self-starting permanent magnet submersible electric motor comprises a rotor assembly having a rotor shaft which made from a shaft having a circular section, a flux barrier and the magnetic structure is salient with the inductance resulting in an additional reluctance torque component and increased motor output, a plurality of permanent magnets is arranged outward radially of the rotor shaft, a stamping and a plurality of conductor bars are arranged inward of radially of the stator body.
[0017] The above and other objects and advantages of the present invention are described here under in greater details with reference to following accompanying non-limiting illustrative drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the preferred embodiments. The figures do not illustrate every aspect of the described embodiments and do not limit the scope of the present disclosure.
[0019] Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.
[0020] Figure 1: illustrates the cross section view of submersible electric motor of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0021] Figure 2: illustrates the stamping design of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0022] Figure 3: illustrates the cross section view of the permanent magnet electric submersible motor rotor of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0023] Figure 4: illustrates the graph of voltage vs. power of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0024] Figure 5: illustrates the graph of voltage vs. efficiency of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0025] Figure 6: illustrates the graph of voltage vs. power factor of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0026] Figure 7: illustrates the graph of voltage vs. current of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0027] Figure 8: illustrates the graph of voltage vs. RPM of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0028] Figure 9: illustrates the graph of voltage vs. head of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0029] Figure 10: illustrates the graph of voltage vs. discharge of the Line/self-starting permanent magnet submersible electric motor according to present invention.
[0030] It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the preferred embodiments. The figures do not illustrate every aspect of the described embodiments and do not limit the scope of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The nature of the invention and the manner in which it works is clearly described in the provisional specification. The invention has various embodiments and they are clearly described in the following pages of the provisional specification. Before explaining the present invention, it is to be understood that the invention is not limited in its application.
[0032] The present disclosure gives an overview of a combination of squirrel cage induction submersible electric motor and permanent magnet electric submersible motor which avoid electronics controller or drive for starting and running in operation reduce the cost of system and reduce of complexity of operation and system.
[0033] Now, as shown in Fig. 1, it illustrates the cross section view of the Line/self-starting permanent magnet submersible electric motor combination in rotor. Now, the motor as shown in FIG. 1 has a stator (12) having a laminated core made of stacked sheet metal laminations, equipped with typically, a single or multi-phase winding (11) which is laid down in the stator core over its entire length. However, the stator (12) of the illustrated embodiment is devoid of other windings (11). A rotor assembly is rotatably mounted concentrically with respect to the stator core.
[0034] Further, the motor comprises, a sand guard (1) mounted on the top of the stator (12), a radial shaft (8) mounted with the sand guard (1) at the top of the stator (12), inside the stator (12) a cable gland (9) being fixed, anupper motor bearing bush (10) being placed with the rotor shaft (16) of the rotor assembly, an upper housing (2) is attached with the middle of a rotor shaft (16) of the rotor assembly, a thrust bearing plate (5) and thrust bearing ring (14) are attached through a thrust bearing housing (6) with a lower motor bearing bush (13) at the end of the rotor shaft (16) of the rotor assembly, a breather diaphragm (7) and a drain plug (15) being placed at the end of the stator body (12).
[0035] Further, as shown in Fig. 2, the rotor assembly having a rotor shaft (16), a flux barrier (17), a plurality of permanent magnets (18), a stamping (19) and a plurality of conductor bars (20).The plurality of conductor bars (20) is sometimes referred to herein as a rotor core.
[0036] The rotor assembly includes a plurality of discrete conductive bars (20) that extend between a pair of end balance rings (24). The discrete conductive bars (20) arranged substantially symmetrically around the rotor body. The quantity, shape, arrangement, and types of bars are dependent on the arrangement of the particular conductor bars (20) of the rotor body. The dimension or shapes of the discrete conductive bars (20) of the rotor assembly are in round, pear, oval, oblong, elliptical, square, rectangle, triangle, equilateral polygon, equiangular polygon, regular polygon and irregular polygon. The plurality of conductor bars (20) and the radius of conductor area are designed as per the induction motor design theory.
[0037] As shown in the Fig. 2, the rotor shaft (16) is made from a shaft having a, but not limited to, circular section, the plurality of conductor bars (20) having corresponding apertures are fitted over this rotor shaft (16), and a copper plate (22) at each end of the conductor stack. The discrete conductor bars (20) pass through the lamination stack and are swaged or welded to the copper end plates (22) as show in Fig. 3. This is provides a squirrel cage type arrangement.
[0038] As such, the invention should not be limited to the squirrel cage. Rather,it is illustrated as one possible example of the squirrel cage. In preferred constructions, the squirrel cage is made of aluminum, which is die-cast into the plurality of conductor bars (20) to form a substantially unitary body. However, other constructions may employ other materials or other processes,(e.g. copper bars brazed to copper end rings) to form the squirrel cage.
[0039] The plurality of conductor bars (20) suitable for use in the rotor body. In preferred constructions, the conductor bars (20) are formed from electrical grade conducting material with other materials also being suitable for use. A central aperture is formed in the conductor bars (20) to receive a rotor shaft (16) to complete rotation of the rotor. The plurality of conductor bars (20) are arranged inward of radially of the stator body (12). The conductor bars (20) are placed with end copper plates (22) with appropriate brazing process or injection molding of the conducting material of the conductors (20).
[0040] The plurality of permanent magnets (18) is arranged outward radially of the rotor shaft (16). The plurality of permanent magnets (18) (North Pole and South Pole permanent magnets by convention the magnets are distinguished by the pole facing radially outwards), are located in slot, cleated or dovetailed section which are formed on the outer surface of the rotor body. The polarity of magnet (18) is arranged and required as per pole decided of the electrical frequency and rotation per minutes.
[0041] The slot retains the magnet when the rotor is spinning at the required speed. It also enables easy installation of the magnets into the rotor. The magnets are also in compression, so even at high centrifugal speed are not subject to tensile failure. The squirrel cage acts to get the rotor rotating, and when the permanent magnets (18) get the rotor into synchronous speed with the rotating filed in the stator, no slip will be experienced by the squirrel cage and no torque will be generated. The flux barrier (17) and the magnetic structure is salient with the inductance resulting in an additional reluctance torque component and increased motor output.
[0042] As shown in Fig. 3, it illustrates the cross section of the permanent magnet electric submersible motor rotor. A rotor assembly stamped with the copper (23) material via stamping (19) with discrete conductive bars (20) inside the stator (12), a copper plate (22) and balancing ring (24) are placed at the end of the rotor shaft (16) of the rotor assembly and a sleeve (21) being attached with the upper end of the rotor shaft (16) of the rotor assembly of the present invention.
[0043] Having the combination of character of an induction and permanent magnet electric submersible motor in rotor, characteristics such as a system has started and run on conventional starter without any complex electronics towards the synchronous speed of permanent magnet (18) electric motor. It will takes over and once at speed will operates synchronous speed with the supply frequency thus the efficiency of the permanent motor is increased to achieve significant energy saving over then of squirrel cage induction submersible motor and possible to use in a solar and agriculture irrigation system and other applications.
[0044] Once the synchronous speed is achieved the induction rotor portion will generate zero torque and consume minimum power. If the permanent magnet rotor losses synchronization then the induction portion of the rotor will generate torque and enables the system to re-synchronize.
[0045] The below table shows the different parameter comparison of squirrel cage induction submersible motor (SCISM) and Line/self-starting permanent magnet submersible electric motor (LSPMSEM)testing with same pump at same head (30m). Further, the Fig. 4 to 10 it shows the graph of the efficiency and another parameters performance vs. voltage of the present invention over the squirrel cage induction submersible motor.

Voltage
415 400 380 360 340 320 300 280
POWER SCISM 5.133 4.955 4.838 4.757 4.695 4.585 4.538 4.454
LSPMSEM 5.543 5.407 5.28 5.269 5.268 5.297 5.322 5.357
Eff. SCISM 77.8 78.41 79.03 78.83 78.27 76.94 75.17 73.02
LSPMSEM 81.18 82.81 84.15 85.02 85.6 85.6 85.27 84.25
Power Factor SCISM 0.71 0.74 0.76 0.79 0.81 0.82 0.82 0.82
LSPMSEM 0.7 0.74 0.81 0.85 0.89 0.91 0.93 0.94
Current SCISM 10.05 9.73 9.62 9.69 9.89 10.12 10.66 11.13
LSPMSEM 11.01 10.49 9.97 9.92 10.08 10.49 11 11.81
RPM SCISM 2896 2888 2875 2862 2844 2811 2788 2753
LSPMSEM 3000 3000 2998 2998 2998 3004 3003 3001
HEAD SCISM 30.84 31.01 30.93 31.05 30.86 31.34 31.1 30.23
LSPMSEM 31.77 31.26 31.73 31.25 31.06 31.28 31.36 31.98
DISCH. SCISM 9.10 8.78 8.68 8.6 8.46 8.02 7.61 7.43
LSPMSEM 10.42 10.66 10.36 10.59 10.64 10.65 10.55 10.21
[0046] As shown in the Fig. 4, it shows the graph of the voltage vs. power of the squirrel cage induction submersible motor and the Line/self-starting permanent magnet submersible electric motor. In the graph, it shows the operation of the present invention with compare to the squirrel cage induction submersible motors. When the voltage increased, the squirrel cage induction submersible motor generates the low power (4 Kv) and when it is in the maximum stage, the power of the squirrel cage induction submersible motor is 5 Kv. Now as shown in graph, the present invention have more power (5 Kv) in the starting low voltage and it is provide flattered power when the voltage is high and provide more power efficiency than squirrel cage induction submersible motor.
[0047] As shown in the Fig. 5, it shows the graph of the voltage vs. efficiency of the squirrel cage induction submersible motor and the Line/self-starting permanent magnet submersible electric motor. The graph shows the efficiency of the present invention over the squirrel cage induction submersible motor at the starting voltage to the higher voltage.
[0048] As shown in the Fig. 6, it shows the graph of the voltage vs. power factor of the squirrel cage induction submersible motor and the Line/self-starting permanent magnet submersible electric motor. In the graph, it shows the operation of the present invention with compare to the squirrel cage induction submersible motors. The power factor of the squirrel cage induction submersible motor is low as the minimum operable voltage and its stable after some voltages. In the present invention, the power factor is optimum as compared to squirrel cage induction submersible motor and it is also shows the high efficiency in power factor then squirrel cage induction submersible motor.
[0049] As shown in the Fig. 7, it shows the graph of the voltage vs. current of the squirrel cage induction submersible motor and the Line/self-starting permanent magnet submersible electric motor. In the graph, it shows the operation of the present invention with compare to the squirrel cage induction submersible motors. In the operation the graph shows that the squirrel cage induction submersible motor takes high current to operate the motor in low voltage, where as in the present invention it takes low current to operate the motor during the low voltage.
[0050] As shown in the Fig. 8, it shows the graph of the voltage vs. RPM of the squirrel cage induction submersible motor and the Line/self-starting permanent magnet submersible electric motor. In the graph, it shows the RPM of the squirrel cage induction submersible motor and the present invention at the starting voltage. The RPM of the squirrel cage induction submersible motor is low at low voltage and the RPM of the present invention is stable at the starting voltage to high voltage.
[0051] As shown in the Fig. 9, it shows the graph of the voltage vs. Head of the squirrel cage induction submersible motor and the Line/self-starting permanent magnet submersible electric motor. The graph shows the difference of the present invention over the squirrel cage induction submersible motor where the squirrel cage induction submersible motor and the present invention are installed at the several height and the efficiency of the both motors are given into the graph. The present invention gives better efficiency then the squirrel cage induction submersible motor.
[0052] As shown in the Fig. 10, it shows the graph of the voltage vs. discharge of the squirrel cage induction submersible motor and the Line/self-starting permanent magnet submersible electric motor. The graph shows the discharging characteristic of the present invention over the squirrel cage induction submersible motor.
[0053] The benefits of this combination in rotor, the squirrel cage induction electric motor rotor is able to operate in correct rotation direction and start the rotation by receiving the starting current. Once rotor starts rotating, the permanent magnets in rotor start synchronization and then after rotor rotate with synchronous speed with e.m.f. field. Here, the induction cage works as a starter of the motor for initial moment and then after rotor works with the principle of permanent magnet motor.
[0054] Furthermore, the benefits of combination in rotor of squirrel cage induction electric Submersible motor is that the squirrel cage work for starting and then after synchronizing rotor with induced e.m.f. in stator due to arrangement of permanent magnet in rotor. After synchronizing the rotor rotation, the squirrel cage power loss becomes zero. So the conductor has no power absorbed characteristic after rotor working with permanent magnet motor principle. Therefore, the rotor loss is very lesser then squirrel cage rotor induction electric submersible motor. The efficiency of the present invention is improved near about permanent magnet electric submersible motor.
[0055] Ultimately the benefits of the present invention is to have rotor with squirrel cage and permanent magnet arrangement in rotor construction design is able to simply start motor on line in a convenient way and to avoid the both independent working disadvantage of electric submersible motor.
[0056] The invention has been explained in relation to specific embodiment. It is inferred that the foregoing description is only illustrative of the present invention and it is not intended that the invention be limited or restrictive thereto. Many other specific embodiments of the present invention will be apparent to one skilled in the art from the foregoing disclosure.
[0057] All substitution, alterations and modification of the present invention which come within the scope of the following claims are to which the present invention is readily susceptible without departing from the spirit of the invention. The scope of the invention should therefore be determined not with reference to the above description but should be determined with reference to appended claims along with full scope of equivalents to which such claims are entitled.

List of Reference Numerals:
1 Sand Guard 13 Lower Motor Bearing Bush
2 Upper Housing 14 Cable Gland
3 Combination in Rotor 15 Radial Shaft Seal
4 Lower Housing 16 Rotor Shaft
5 Thrust Bearing Plate 17 Flux Barrier
6 Thrust Housing 18 Plurality of Permanent Magnet s
7 Breather Diaphragm 19 Stamping
8 Drain Plug 20 Plurality of Conductor Bars
9 Thrust Bearing Ring 21 Sleeve
10 Upper Motor Bearing Bush 22 Copper Plate
11 Winding 23 Copper
12 Stator 24 Balancing ring