Brushless dc motor

IT convert the electrical to mechanical

1. Brushless DC Motors Presented by K umaresan A (161me527) Moutheepan S (161me542)

2. Brushless DC Motors

3. Contents… Introduction Motor basics Principles of BLDC motor Construction Hall sensors Dismantling of BLDC motor Advantages Disadvantages Applications Conclusion

4. Introduction… Classical DC motors are no doubt good and simple but inefficient in some ways. Although dc motors possess good control characteristics and ruggedness, their performance and applications are inhibited due to sparking and commutation problems. The Permanent Magnet Brushless DC (PMBLDC) motor is able to overcome the limitations mentioned above and satisfy the requirements of a variable speed drive.

5. What is a motor Converts electrical energy into kinetic energy How it works Motor Basics

6. Brushless DC Motor(BLDC) Principles A BLDC is simply a normal dc motor turned inside out, that means the coil is on the out side and the magnets are inside The stator consists of several coils which current is led through Creating a magnetic field that makes the rotor turns

7. Construction Stator consists of stacked steel laminations with windings placed in the slots that are axially cut along the inner periphery Rotor is made of permanent magnet and can vary from two to eight pole pairs with alternate North (N) and South (S) poles. Ferrite magnets and Rare earth alloy magnets are used in rotor

8. U nlike a brushed DC motor, the commutation of a BLDC motor is controlled electronically. I t is important to know the rotor position in order to understand which winding will be energized following the energizing sequence. R otor position is sensed by different ways some of them are Hall sensors 2) Optical encoders

9. Hall Sensors W hen a magnetic field applied to a system with electric current a hall voltage Perpendicular to the field and to current is generated. This was discovered by Edwin Hall in 1879.

10. Torque/Speed Characteristics

11. DISASSEMBLED VIEW OF BRUSHLESS DC MOTOR

12. Advantages Increased Reliability & Efficiency Longer Life Elimination of Sparks from Commutator Reduced Friction Faster Rate of Voltage & Current

13. Disadvantages Requires Complex Drive Circuitry Requires additional Sensors Higher Cost Some designs require manual labor (Hand wound Stator Coils)

14. Applications Consumer: Hard Drives, CD/DVD Drives, PC Cooling Fans, toys, RC airplanes, air conditioners

15. Medical: Artificial heart, Microscopes, centrifuges, Arthroscopic surgical tools, Dental surgical tools and Organ transport pump system .

16. Conclusion Although Brushless DC Motors are more expensive of the same kW rating than conventional DC Motor but there are many advantages. Brushless DC Motors can run when submerged in fluids. Brushless DC Motor does not produce brush or commutator particles or gases as by-products of operation.