Brush-Less DC Motor

INTRODUCTION:  BRUSH-LESS D.C. MOTOR

• 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 .

MOTOR…

>> Converts electrical energy to mechanical energy.

ORIGIN...

>>  Nicola Tesla introduces electric motor in December 1889.

 >> He identifies the principle of rotating magnetic field.

MAIN PARTS OF BRUSHED MOTOR:

Commutator :

>> Facilitate collection of current from the armature conductors.

Brush :

> Collects current from the commutator.

CLASSIFICATION:

BRUSH-LESS D.C. MOTOR:

• Has no brushes and commutators.
• Rotation of the rotor depends on the accurate position with stator.
• Detected by Hall Sensor, mounted on rotor.

WORKING OF BRUSH-LESS D.C. MOTOR:

•  As there is no commutator ,the current direction of the conductor on the stator controlled electronically.

• Rotor consists the permanent magnet where as stator consist a no. of windings. Current through these winding produces magnetic field and force.

Hall sensor used to determine the position during commutation.

SPEED-TORQUE CHARACTERISTICS:

PROCEDURE:

In BLDC motor PM are on the rotor & electromagnets are on the stator controlled by software. Thus the advantages are:

1.Because of computer control it is more precise & more efficient.

2.There is no sparking & less electrical noise.

 3.Voltage and current rating is high.

4.High speed can be achieved.

5.As there is no brushes it requires no servicing.

6.It has longer life.

7.Low Radio Frequency Interference and electromagnetic Interference.

DISADVANTAGES:

• Requires Complex Drive Circuitry.
• Requires additional Sensors.
• Expensive.
• Some designs require manual labor. (Hand wound Stator Coils.

APPLICATIONS:

PMBLDC motors are increasingly being used in a wide spectrum of applications:

1. domestic equipment,
2. automobiles
3. information technology equipment
4. industries
5. public life appliances
6. transportation
7. aerospace, defense equipment, power tools, toys, vision and sound equipment
8. medical and health care equipment ranging from micro-watts to megawatts.

REFERENCE:

http://en.wikipedia.org/wiki/Alternator

http://en.wikipedia.org/wiki/Electric_motor

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