WE CLAIM:
1. A system for positive balancing of electrical motor rotors having a mass imbalance, said rotor 200 comprising:
o a shaft 202 having a first end 202a and a second end 202b;
o permanent magnets 216 and silicon steel 218 being molded with plastic 214 and assembled with said shaft 202,
■ said plastic mold 214 and silicon steel 218 defining an operative first outer surface 212a and an operative second outer surface 212b on a first end 202a and a second end 202b of said plastic mold 214, respectively;
■ one or more recesses 208 being configured on said operative first 212a and second outer surfaces 212b at predetermined angular locations; and
■ said one or more recesses 208 configured to receive a predetermined amount of a mass;
said system comprising:
- a first fixture 300 comprising:
o a first support 302 configured to receive a first bearing 304 and said first end 202a of said shaft 202 operatively therein;

o a second support configured to receive a second bearing 330 and said second end 202b of said shaft 202 operatively therein;
o a driving means, operatively connected to rotor periphery 206 of said rotor 200, configured to drive said rotor 200;
- a plurality of accelerometers 310 configured to measure vibrations due to imbalance mass of said rotor 200 at first end 202a side and second end 202b side during rotations thereof, wherein said accelerometers 310 generate vibration signals 312;
- a plurality of filters 314 configured to receive and filter said vibration signals 312 from said accelerometers 310 to obtain filtered signals 316;
- a plurality of vibration meters 318 configured to receive said filtered signals 316 and determine and display magnitude of said vibrations;
- a tachometer 320 configured to measure speed of rotationand generate a signal 322;
- a phase angle meter 324 configured to measure a phase angle delay between the signal 322 from said tachometer 320 and said filtered signals 316 for detecting the angular location of the imbalance on said rotor 200 at first end 202a side and second end 202b side, relative to a datum position 328;

- a display unit for displaying the phase angle, the magnitude of bearing vibration and mass of imbalance;
- a second fixture comprising:
o a first support 302 configured to receive a first bearing 304 and said first end 202a of said shaft 202 operatively therein;
o a second support configured to receive a second bearing 330 and said second end 202b of said shaft 202 operatively therein;
o a driving means, operatively connected to one of said first end 202a and said second end 202b of said shaft 202, configured to drive said shaft 202;
wherein the balancing mass(es) 402 being received in said one or more recesses 208
• to reduce the mass imbalance; and
• permanently.

2. The system as claimed in claim 1, wherein said balancing mass(es) 402 for positive balancing is at least one of brass, aluminum and a combination thereof.
3. The system as claimed in claim 1, wherein said balancing mass(es) 402 being in form of strips.

4. The system as claimed in claim 4, wherein said strips having a cylindrical cross section.
5. The system as claimed in claim 1, wherein the number of recesses 208 configured on said first outer surface 212a and second outer surface 212b being in the range of 6 to 10, preferably 8.
6. A method for positive balancing of electrical motor rotors, said method comprising:

- providing a rotor 200 having a mass imbalance;
- mounting said rotor 200 on a first fixture 300, wherein a first end 202a and a second end 202b of a shaft 200 of said rotor 200 are received in a first bearing 304 and a second bearing 330 supported on a first 302 and second support, respectively;
- rotating said rotor 200 while being mounted on said first fixture 300 at a predetermined rotational speed, by coupling said rotor 200 with a driving means;
- measuring vibrations of said rotating rotor 200 by using a plurality of accelerometers 310 to determine vibrations due to imbalance mass of said rotor 200 at first end 202a side and second end 202b side during rotation thereof and generating vibration signals 312;

- filtering said vibration signals 312 employing a plurality of filters 314 to obtain filtered signals 316;
- determining and displaying magnitude of said filtered signals 316 employing a plurality of vibration meters 318;
- measuring rotation speed of said rotor 200 by employing a tachometer 320 and generating a corresponding signal 322 therefrom;
- determining a phase angle between said filtered signals 316 and said signal 322 generated by a tachometer 320, thereby detecting the angular location of said imbalance on said rotor 200 at first end 202a side and second end 202b side relative to a datum position 328;
- determining the position of mass imbalance and the amount of mass to be inserted;
- providing a second fixture and operably securing said rotor 200 on to said second fixture;
- receiving and securing one or more balancing mass(es) 402 in said one or more recesses 208 to reduce the mass imbalance; and
- Repeating the above steps till mass imbalance of said rotor 200 is below a predetermined value.

7. The method as claimed in claim 6, wherein said balancing mass(es) 402 for positive balancing is at least one of brass, aluminum and a combination thereof.
8. The method as claimed in claim 6, wherein said balancing mass(es) being received in said one or more recesses permanently.
9. The method as claimed in claim 6, wherein said balancing mass(es) 402 being in form of strips.
10. The method as claimed in claim 10, wherein said strips having a cylindrical cross section.
11. The method as claimed in claim 6, wherein the number of recesses 208 configured on said first outer surface 212a and second outer surface 212b being in the range of 6 to 10, preferably 8.