Description:FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

ENERGY EFFICIENT PERMANENT MAGNET SYNCHRONOUS MOTOR FOR SOLAR SUBMERSIBLE PUMP

ROTO ENERGY SYSTEMS LIMITED
PLOT NO. 31, SECTOR ECOTECH XII
GREATER NOIDA-201308
INDIA

The following specification particularly describes the invention and the manner in which it is to be performed
FIELD OF THE INVENTION
The present invention generally relates to the field of submersible pumps and permanent magnet synchronous motors (PMSM). More specifically, it pertains to a permanent magnet synchronous motor for solar submersible pump.
BACKGROUND OF THE INVENTION
Before proceeding into the details of present invention, some important terms and definitions are as below-
Rotor- In context of electric motors, the rotor refers to the rotating element of the motor that transmits mechanical energy to the load. The rotor particularly interacts with magnetic field produced by stator to generate torque and cause rotation.
Stator- Stator is defined as the stationary part of the electric motor. It consists of windings of copper wire wound around an iron core. The primary function of the stator is to generate rotating magnetic field, when electric current is supplied. The magnetic field further interacts with the rotor to produce mechanical torque, which initiates the operation of the motor.
Synchronous motor- Synchronous motor is a type of AC motor, where the rotation of the rotor is synchronized with the frequency of the supply current at a steady state. Synchronous motors operate on the principle of synchronism, where the rotor rotates at the same speed as the rotating magnetic field produced by the stator windings. (https://en.wikipedia.org/wiki/Synchronous_motor#:~:text=A%20synchronous%20electric%20motor%20is, integer%20number%20of%20AC%20cycles.)
Permanent magnet synchronous motor- Permanent Magnet Synchronous Motor (PMSMs) is a type of synchronous motor where the rotor contains permanent magnets rather than windings while its stator resembles that of an induction motor. The stator is stationary part carrying armature winding of the motor, because of which EMF is induced in the motor. The number of slots on stator determine the speed of the rotating magnetic field. The permanent synchronous motor works in similar manner as synchronous motor works. The working depends upon the rotating magnetic field that generates electromotive force at synchronous speed. Stator winding usually gets energized with supply of 3-phase, which in turn creates rotating magnetic field between the air gaps, which further produces a torque, when the rotor field poles hold the rotating magnetic field at a synchronous speed and the rotor rotates continuously, initiating the operation of the motor. (https://www.elprocus.com/what-is-a-permanent-magnet-synchronous-motor-its-working/)
Submersible pumps- Submersible pump is also known as electrical submersible pump, which is a water pump that is completely submerged in water and is used for various applications. The electric motor used in this process is hermetically sealed and also close coupled to the pump’s body. (https://www.crompton.co.in/blogs/pumps/what-is-a-submersible-pump-understanding-its-working-and-applications)
Cogging torque- Cogging torque is the consequence i.e., torque generated by interaction (magnetic attraction) between rotor-mounted permanent magnets field and the stator teeth which produces reluctance variations depending on rotor position. It occurs when the rotor aligns itself with the magnetic poles of the stator in the absence of electrical power. (https://en.wikipedia.org/wiki/Cogging_torque)
Torque pulsation- Torque pulsation refers to variations or fluctuations in torque output from an electric motor, particularly Permanent Magnet Synchronous Motors (PMSMs). Reduction of torque pulsation is crucial for smooth and consistent operation of electric machines with optimized motor performance. (https://www.researchgate.net/publication/3930019_Pulsating_torque_reduction_for_permanent_magnet_AC_motors#:~:text=Pulsating%20torque%20represents%20the%20sum,ampli%EF%AC%81ed%20in%20variable%20speed)
Conventional permanent magnet motor based submersible pumps and associated problems:
In general, the conventional and commonly available permanent magnet based submersible pump motor is built around a rotor with 4 poles and a stator with 24 slots. However, such design produces non-sinusoidal flux distribution in the annular air gap between the stator and the rotor, thereby giving rise to relatively large cogging torque and torque pulsations, which in turn results in mechanical and electrical noise that distorts the wave shape of electrical power supply in mains as well as in the motor. High cogging torque impacts the operation of entire device and cause vibrations, tensions and noise. It results in braking torque and subsequent power losses and leads to faster wear and tear of machine structural elements. High cogging torque values also cause problems with rotational speed adjustment.
Thus, the cogging torque and pulsation torque must be reduced in order to ensure the proper operation of the motor without such noise and vibrations.
Existing 10 pole and 12 slots based PMSM motor and associated problems:
There are variety of 10 rotor poles and 12 stator slots based PMSM motors available commercially, however, such motors fails to reduce the cogging torque to less than 1% of nominal torque and also fails to reduce the torque pulsation to less than 5% of nominal torque, reduction of torque to such levels is very crucial in order to ensure smooth starting as well as operation of the pump without noise and vibrations, however, none of the existing patents or non-patents literatures discloses such torque reductions, which indicates that no one till the date is able to reduce the cogging torque and pulsating torques to such levels.
Innovative approach by present invention-
Thus, in order to address these drawbacks associated with higher cogging torque values, the inventors of present invention innovatively altered the design and geometry of the rotor and stator assembly in the permanent magnet syncronous motor by way of some technical modifications, which results in improvement of the flux distribution in the air gaps between the stator and the rotor resulting in sinusoidal flux distribution which greately reduces the cogging torque and perfectly sinusoidal back electromotive force (EMF), that reduces total harmonic distortions produced in power line.
Instead of 4 rotor poles and 24 stator slots, a different slot/pole combination i.e., 10 rotor poles and 12 stator slots geometry has been optimized in present invention, that facilitates sinusoidal flux distribution along with this, the present invention also provides a field oriented control based driver circuitry that ensures full featured performance of the motor throughout large window of mains voltage and frequency ranges.
Prior art patents
Patent Application no. US20100289370A1 discloses “Synchronous motor having 12 stator teeth and 10 rotor poles”
The above cited patent discloses an electric machine, particularly a synchronous machine comprising a stator arrangement with twelve stator teeth and a rotor with ten rotor poles, the rotor poles are separated by air gaps and the rotor poles are formed as sine poles. The disclosed machine has the advantage that the cogging torque and the harmonic moments can be significantly reduced compared to an electric machine without sine poles. Each rotor pole further has permanent magnets whose north pole-south pole direction extends radially. (Prior art figure 1)
Both the innovations discloses a permanent magnet synchronous motor with 12 stator slots and 10 rotor poles, however, the present invention comprises M470-05A lamination, which is not disclosed in cited article. Further, there is no air gap shaping in present invention, which is there in cited patent. Further, many features of present invention are missing in cited patent, making cited patent different from present invention.
Patent application no. US6034460 discloses “Permanent magnet rotating electronic machine and electrically driven vehicle employing same”
The aforementioned patent discloses a permanent magnet rotating electronic machine comprising a stator with stator core, multiphase stator windings wound around stator core, a rotor comprising rotor core and permanent magnets inserted in permanent magnet holes formed in rotor core and a shaft. The ratio of rotor with permanent magnets and stator poles is 10:12 that indicates there are 10 rotor poles and 12 stator slots. Further, the least common multiple (LCM) of no. of rotor with permanent magnets and no. of stator poles is 60 per rotations. Thus cogging torque is smaller and no. of pulsations per rotation is larger. (Prior art figure 2)
Number of stator slots and rotor poles and LCM value is similar in both the patents, however, the cited patent does not discloses NdFeB magnet and M470-05A lamination. Further, the cogging torque and torque pulsation as disclosed in present invention is not there in cited patent.
Patent Application No. CN201409069Y discloses “Hybrid Excitation doubly salient motor”
The cited patent discloses a mixed excitation biconvex pole motor comprising a rotor formed by tooth-space core laminations, stator fixed in the casing comprises U-shaped iron cores arranged at intervals , three phase armature winding, single phase excitation winding and casing made up of magnetic material. Further, permanent magnet i.e., neodymium is arranged between U shape core and casing. Further, the rotor comprises of 10 teeth/poles and stator is equipped with 12 slots. (Prior art figure 3).
No. of rotor poles and stator slots in both the patents is same, however, the cited patent does not disclose M470-05A lamination but use of Neodymium magnet is disclosed. Further, the cogging torque and torque pulsation as disclosed in present invention is not there in cited patent.
Non-patents literature
Chun Yu Hsiao; Sheng-Nian Yeh; Jonq-Chin Hwang; A Novel cogging torque simulation method for permanent magnet synchronous machines; Energies 2011; 4; 2166-2179
The above cited research article discloses a rotor skewed structure used to reduce cogging torque of permanent magnet synchronous machine. The disclosed structure comprises a 10-pole (rotor) and 12-slot (Stator) permanent magnet synchronous motor having 1000mm axial length of inner rotor made of laminating steel sheets, stator winding connected for 3-phase operation. The least common multiple (LCM) for 12 slot and 10 pole structure is 60 and period of cogging torque is 6o. (Prior art figure 4)
Number of stator slots and rotor poles and LCM value is similar in both the patents, however, the cited article fails to disclose the presence of M470-05A lamination and NdFeB magnet and other important features of present invention such as power factor, RPM efficiency, speed torque profile etc. Cogging torque is 0.0007Nm, which is less than nominal torque.
Vincenzo Madonna, Paolo Giangrande, Luca Lusuardi, Andrea Cavallini, Chris Gerada, Michael Galea; Thermal overload and insulation aging of short duty cycle, aerospace motors; IEEE Transactions on Industrial Electronics; May 2019
The above cited research article discloses machine actuated by a permanent magnet synchronous machine (PMSM) through a coupling gearbox whereas the PMSM is supplied by power electronics converters (PECs). The machine is a surface mount PMSM with a dual three-phase winding configuration i.e. two identical set of windings are wound on the same stator core Each winding set is supplied by a separate PEC, thus the PMSM can be operated by feeding both sets simultaneously or by supplying only one of the two sets. The PMSM is 12 stator slots and 10 rotor poles motor where the outer diameter of the stator is 60mm. (Prior art figure 5)
No. of stator slots and rotor poles in both the innovations is similar, however, there are differences in outer diameter of the stator, which is 60mm in cited article and 70mm in present invention. Further, other features such as lamination, use of neodymium magnet, power factor, RPM efficiency, speed torque profile etc are also not disclosed in the cited patent.
Dahaman Ishak, Z. Q. Zhu, and David Howe; Comparison of PM Brushless Motors, Having Either All Teeth or Alternate Teeth Wound; IEEE transactions on energy conversion, Vol. 21, No. 1, March 2006
The aforementioned research article discloses a three phase permanent magnet brushless motor with 12 stator slots and 10 rotor poles and 1 mm airgaps. The inner diameter of the stator is 28.5mm and outer diameter of the stator is 50mm whereas the outer diameter of the rotor is 27.5mm. Further, the smallest common multiple (SCM) is 60, thus there is very small cogging torque, due to larger SCM value. (Prior art figure 6)
No. of stator slots and rotor poles in both the innovations is similar, however, there are differences in outer & inner diameter of the stator, which is 50mm and 27.5mm resp. in cited article and 70mm & 44.9mm resp. in present invention.
Ahmed Hemeida, Mohamed Y Metwly, Ayman S. Abdul-Khalik and Shehab Ahmed; Optimal design of a 12-slot/10 pole six phase SPM machine with different binding layouts for integrated on-board EV battery charging (Prior art figure 7)
The above mentioned research article discloses a six phase 12 slot and 10 pole fractional slot concentrated winding (FSW) based surface mounted permanent magnet machine with different binding layouts for integrated on-board EV charging. The core of the rotor and stator is made up of copper M235-35A and the magnet of rotor is NdFeb_1.26. Further, the stator outer and inner diameter is 282.6mm and 192.4 mm respectively, air gap length is 1mm and rotor inner diameter is 190.4mm.
No. of stator slots and rotor poles in both the innovations is similar, however, the inner and outer diameter of the stator is quite larger in cited article in comparison to present invention.
Dong Yan, Yan Yan, Yiqui cheng, Liyan Guo, Tingna Shi; Research on cogging torque reduction method for permanent magnet synchronous motor accounting for magnetic poll edge effect; IET Electric Power Applications; 7 September 2023
The above cited research article discloses a method for suppressing cogging torque of PMSM considering the magnetic pole edge effect by designing a 12-slot 10-pole non-uniform herringbone step skew rotor PMSM. The stator inner and outer diameter is 78mm and 155mm respectively, rotor inner diameter is 45mm & air gap length is 2mm. The proposed structure reduces cogging torque by more than 40% and ripple torque by more than 22% and also eliminate axial unbalance magnetic force. (Prior art figure 8)
No. of stator slots and rotor poles in both the innovations is similar, however, the inner and outer diameter of the stator in cited article is 78mm and 155mm resp., which is higher than the diameter of stator disclosed in present invention i.e.,70mm O.D and 44.9mm I.D.
HAO Zhongxian, ZHU Shijia, PEI Xiaohan, HUANG Peng, TONG Zheng, WANG Benyuan, LI Deyin; Submersible direct-drive progressing cavity pump rodless lifting technology; Petroleum exploration and development Volume 46, Issue 3, June 2019
The above cited research article discloses a submersible permanent magnet synchronous low speed motor having 10 rotor poles with permanent magnet and 12 stator slots. The inner diameter of the stator is 60mm and air gap length is 0.4mm
No. of stator slots and rotor poles in both the innovations is similar. The difference lies in the diameter of the stator.
Table 1- Comparison of present invention with cited patents and non-patents journals

OBJECT OF THE PRESENT INVENTION

The primary objective of the present invention is to disclose a permanent magnet based synchronous motor for solar submersible pump having a high-power factor and efficiency.

Another objective of the present invention is to disclose a permanent magnet based synchronous motor for solar submersible pump with perfectly sinusoidal back EMF and reduced of cogging torque.

One more objective of the present invention is to disclose a permanent magnet based synchronous motor for solar submersible pump with an optimal flux distribution in the air gap.
SUMMARY OF THE PRESENT INVENTION
In present invention, the design and geometry of the rotor and stator assembly in the permanent magnet syncronous motor is altered by way of some technical modifications, which results in improvement of the flux distribution in the air gaps between the stator and the rotor resulting in sinusoidal flux distribution which greately reduces the cogging torque and perfectly sinusoidal back electromotive force (emf), that reduces total harmonic distortions produced in power line. Further, the present invention also provides a field oriented control based driver circuitry that ensures full featured performance of the motor throughout large window of mains voltage and frequency ranges.
The permanent magnet synchronous motor (PMSM) as disclosed in present invention consists of stator assembly of 44.9mm inner & 70mm outer diameter including 12 stator slots (002) with aluminum/copper windings and M470-05A electrical sheet lamination core and a rotor assembly of 23mm inner and 43.9mm outer diameter, consisting 10 rotor poles (001) having core embedded with NdFeB magnets (004) connected to rotor shaft (003). The stator and the rotor are arranged in the motor casing, two ends of which are sealed and connected with other external elements through connecting devices. The stator is fixed on casing assembly and rotor is placed in center of stator. The design of PMS motor of present invention improves the flux distribution in the air gaps between stator and rotor resulting in sinusoidal flux distribution which greately reduces the cogging torque, torque pulsations and perfectly sinusoidal back electromotive force, that reduces total harmonic distortions produced in power line.
BRIEF DESCRIPTION OF DRAWINGS
Fig 1 – 8 Prior art figures
Fig 9- Submersible pump assembly
Numbering details-
1) Stator tube
2) Stator stack
3) Winding cap for upper
4) Motor shaft
5) Balancing ring for upper
6) Magnet
7) Balancing ring for lower
8) Stator winding
9) Rotor stack
10) Bearing
Fig 10- Rotor and stator arrangement for PMSM motor assembly
Numbering details-
(001) Rotor assembly with 10 rotor poles
(002) Stator assembly with 12 stator slots
(003) Rotor shaft
(004) Neodymium Magnets
(005) Stator outer
(006) Steel cage
(007) Air gaps
Fig 11- Graph of comparison of back EMF of 4 pole and 10 pole motor of present invention
Fig 12- Graph of comparison of cogging torque of 4 pole and 10 pole motor of present invention
Fig 13- Graph of comparison of airgap flux of 4 pole and 10 pole motor of present invention
Fig 14- Efficiency map comparison of 4 pole and 10 pole motor of present invention `1
Fig 15- Graph of comparison of torque pulsations of 4 pole and 10 pole motor of present invention
Fig 16- Graph of comparison of speed-torque of 4 pole and 10 pole motor of present invention
Fig 17- Graph of comparison of flux linkage of 4 pole and 10 pole motor of present invention
Fig 18- Graph of comparison of flux linkage of 4 pole and 10 pole motor of present invention
The permanent magnet synchronous motor based solar submersible pump is now disclosed in detail with reference to the accompanying drawings.
DETAILED DESCRIPTION OF INVENTION
The present invention discloses a submersible pump motor built around permanent magnet synchronous motor (PMSM). The design and geometry of the PMSM motor in present invention is technically modified to achieve maximum efficiency and minimum cogging torque.
In present invention, the design and geometry of the rotor and stator assembly in the permanent magnet syncronous motor is altered by way of some technical modifications, which results in improvement of the flux distribution in the air gaps between the stator and the rotor resulting in sinusoidal flux distribution which greately reduces the cogging torque and perfectly sinusoidal back electromotive force (emf), that reduces total harmonic distortions produced in power line. Instead of 4 rotor poles and 24 stator slots, a different slot/pole combination i.e., 10 rotor poles and 12 stator slots geometry has been optimized in present invention, that facilitates sinusoidal flux distribution. Along with this, the present invention also provides a field oriented control based driver circuitry that ensures full featured performance of the motor throughout large window of mains voltage and frequency ranges.

CONSTRUCTIONAL DETAILS OF PRESENT INVENTION:
In preferred embodiment, the present invention discloses a submersible pump built around permanent magnet synchronous motor. The design and geometry of the PMSM motor is altered, in order to reduce the cogging torque and to maximize the efficiency of the submersible pump disclosed in present invention.
Submersible Pump motor of present invention-
The submersible pump motor by way of figure 1 is illustrated below for better understanding of the same:
Figure 1 discloses submersible pump motor assembly consisting of:
- A stator tube (1);
- A stator stack (2) made up of high quality electro-steel to reduce eddy current loses. These laminates are stacked tightly together to form a compact assembly. This reduces any microphonic noises arising out of magneto-striction effect;
- Winding cap for upper (3);
- Motor shaft (4) made up of steel;
- rotor stack (9) consisting of Balancing ring for upper (5) and balancing ring for lower (7);
- Magnets (6) inside the rotor and stator tube;
- An integral stator winding (8) made up of insulated copper wire, around which stator is built;
- Bearings (10) to secure the main shaft (4)
Permanent magnet synchronized motor (PMSM)-
The major innovations lies in the design of the permanent magnet synchronized motor. As, in present invention, the design of PMSM motor is altered by optimizing the choice of stator slots and rotor poles. Thus, in order to achieve a least common multiple (LCM) of 60, 10 rotor poles and 12 stator slots are used in the motor, which also reduces the torque pulsation and cogging torque.
The design and geometry of the rotor and stator assembly in the permanent magnet syncronous motor is altered by way of some technical modifications, which results in improvement of the flux distribution in the air gaps between the stator and the rotor resulting in sinusoidal flux distribution which greately reduces the cogging torque and perfectly sinusoidal back electromotive force (emf), that reduces total harmonic distortions produced in power line. Further,
The rotor and stator assembly in PMSM motor by way of figure 2 is further disclosed below in details for clear understanding of the contents of the present invention:
The PMSM motor assembly as disclosed in present invention has following constructional features:
Stator assembly with 12 stator slots (002) with windings of copper or aluminum wire. Stator further consists of core made of laminations of electrical sheet i.e., M470-05A to reduce eddy current losses. The windings made from copper or aluminum are placed in slots on the stator core and are connected to external power supply. Windings are arranged in such as way that when AC current flows through them, a rotating magnetic field is generated in the air gap between the stator and the rotor. The inner and outer diameter of the stator is 44.9 mm and 70 mm respectively.
Rotor assembly with 10 rotor poles (001) having NdFeB magnets i.e., neodymium iron boron magnets (004) embedded in core of the rotor, which is further connected to the rotor shaft. The magents produce magnetic field, which interacts with the rotating magnetic field generated by the stator windings, causing the rotation of the rotor. The inner and outer diameter of the rotor is 23mm and 43.9 mm respectively.
The stator and rotor assembly is further, enclosed in steel cage (006). The stator and the rotor are correspondingly arranged in the motor casing, two ends of the motor casing are respectively sealed and connected with other external elements through connecting devices. The stator assembly is fixed on casing assembly and the rotor assembly is placed in the center of the stator.
Further in built design of the motor assure perfect sine wave Back EMF, which results in low harmonic content.
The design is optimized with respect to standard monofacial solar module cell, as the motor Current and voltages are chosen to match commercially available monofacial solar module such as 535 Wp rating. Furthermore, the RPM efficiency profile of the motor is maintained within 20% of the rated rpm, which extend the nominal working speed of the motor.
No. of rotor poles 10
No. of stator slots 12
Magnet used NdFeB (neodymium Iron Boron magnet)
Lamination used M470-05A
Inner diameter of stator 44.9mm
Outer diameter of stator 70mm
Inner diameter of rotor 23mm
Outer diameter of rotor 43.9 mm
Speed-torque profile Flat (Full torque even at low speed)
Power factor 0.9 and above
Table 2- Constructional features of PMSM motor.
The optimum design and choice of 10 rotor poles with 12 stator poles provides an LCM i.e., least common multiple value of 60, which thereby reduces the torque pulsation to less than 5% of nominal torque and cogging torque to zero, which results in smooth start and operation of the submersible pump with less noise and vibrations, thus enhance the efficiency of working and also enhances the life of the same.

Further, the same also optimized air gap flux between the stator and the rotor. Further, there is pure sinusoidal back electromotive force (EMF) with minimum harmonic distortions. The altered design greatly reduced power consumption compared to any motor type through optimum use of sensor less field oriented controlled driver electronics.
Results and Discussion:
A lot of experimentation was conducted with the help of simulation software
The comparison table of various parameters of performance of 4 pole and 10 pole submersible motor pumps is as below:
Parameter 4 pole 10 pole Interpretation and remarks
back EMF (Vrms) @3000 rpm 88.5
Cogging Torque (Nm) (rms) 0.15
Airgap Flux 88.5
Efficiency 87.8
Torque Pulsations (Nm) 4.8±8%
Speed-Torque 0 at 4000 rpm
Flux
Linkage 1(wb) 0.0462

Novelty of the present invention is duly clear as per non-disclosure of same in existing patents and non-patents literature.

Inventive step by way of technical advancement of knowledge lies in innovatively altering design and geometry of the rotor and stator assembly in the permanent magnet syncronous motor by way of some technical modifications, which results in improvement of the flux distribution in the air gaps between the stator and the rotor resulting in sinusoidal flux distribution which greately reduces the cogging torque and perfectly sinusoidal back electromotive force (emf), that reduces total harmonic distortions produced in power line. The technical modifications are:
Industrial Application is duly clear as present invention reduces the cogging torque and torque pulsation generated in the motor, which in turns ensures the smooth start and operation of the pump with less noise and vibrations, which further increases the life of the pumps by reducing the wearing and tearing of the same. Thus, present invention is of great benefit to the manufacturers and consumers of permanent magnet synchronous motors.
As used herein, the word "a" or "an" should be understood as not excluding plural elements or operations, unless such exclusion is explicitly recited. Furthermore, references to "one embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

The present disclosure is not to be limited in scope by the specific embodiments described herein. Other embodiments and modifications apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings are intended to fall within the scope of the present disclosure. Furthermore, although the present disclosure has been described herein in the context of above, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any pump for similar purpose.
, Claims:WE CLAIM:
1. A permanent Magnet Synchronized motor assembly for solar submersible pump characterized in that :
- the stator is of 44.9mm inner & 70mm outer diameter consists of 12 stator slots (002) with aluminum/copper windings and M470-05A electrical sheet lamination core ;
- the rotor placed in center of stator is of 23mm inner and 43.9mm outer diameter, consists of 10 rotor poles (001) having core embedded with NdFeB magnets (004) connected to rotor shaft (003);
- the stator is fixed on casing assembly and rotor is placed in center of stator.
- two ends of the casing are sealed and connected with other external elements (Like controller) through connecting devices;
- the RPM efficiency profile of the motor is maintained within 20% of the rated rpm.
2. The permanent Magnet Synchronized motor assembly as claimed in claim 1 wherein aluminum/copper windings are made using Fractional Slot Concentrated Winding to ensure perfect sine wave Back EMF and low harmonic content.
3. The permanent Magnet Synchronized motor assembly as claimed in claim 1 wherein the Pole shape of the rotor magnet space at air gap is 0.5mm
4. The permanent Magnet Synchronized motor assembly as claimed in claim 1 wherein the cogging torque is 0.15 Nm
5. The permanent Magnet Synchronized motor assembly as claimed in claim 1 wherein the back electromotive force (emf) is perfectly sinusoidal.