This presentation discusses brushless DC motors. It explains that brushless DC motors do not have brushes, instead using electronics for commutation. This makes them highly efficient over a wide speed range with smooth operation and holding torque when stationary. The presentation describes the basic working principles of brushless DC motors, including their rotor, stator, and electronic control of electromagnets. It discusses how brushless DC motors eliminate the need for commutators through electronic position sensing and switching. Examples of applications are provided, along with advantages like increased efficiency and high performance. Disadvantages include higher cost compared to brushed DC motors and limited high power capabilities.

1. PRESENTATION ON
BRUSHLESS DC MOTOR
PREPARED BY SOUVIK DUTTA

2. BRUSHLESS DC MOTORS
• BRUSHLESS DC MOTOR MAY BE DESCRIBED AS ELECTRONICALLY COMMUTED
MOTOR WHICH DO NOT HAVE BRUSHES. THESE TYPES OF MOTORS ARE HIGHLY
EFFICIENT IN PRODUCING LARGE AMOUNT OF TORQUE OVER A VAST SPEED
RANGE. IN BRUSHLESS MOTORS, PERMANENT MAGNETS ROTATE AROUND A
FIXED ARMATURE AND OVERCOME THE PROBLEM OF CONNECTING CURRENT TO
THE ARMATURE. COMMUTATION WITH ELECTRONICS HAS LARGE SCOPE OF
CAPABILITIES AND FLEXIBILITY. THEY KNOWN FOR SMOOTH OPERATION, AND
HOLDING TORQUE WHEN STATIONARY.

3. WORKING PRINCIPLE OF MOTOR
• IN BRUSHES MOTORS, THERE ARE PERMANENT MAGNETS ON THE
OUTSIDE AND A SPINNING ARMATURE WHICH CONTAINS
ELECTROMAGNET IS INSIDE.
• THESE ELECTROMAGNETS CREATE A MAGNETIC FIELD IN THE
ARMATURE WHEN POWER IS SWITCHED ON AND HELP TO
ROTATES ARMATURE.
• THE BRUSHES CHANGE THE POLARITY OF THE POLE TO KEEP THE
ROTATION ON OF THE ARMATURE.
• THE BASIC PRINCIPLES FOR THE BRUSHED DC MOTOR AND FOR
BRUSHLESS DC MOTOR ARE SAME I.E., INTERNAL SHAFT POSITION
FEEDBACK.

4. • BRUSHLESS DC MOTOR HAS ONLY TWO BASIC PARTS:
ROTOR AND THE STATOR.
• THE ROTOR IS THE ROTATING PART AND HAS ROTOR
MAGNETS WHEREAS STATOR IS THE STATIONARY PART
AND CONTAINS STATOR WINDINGS.
• IN BLDC PERMANENT MAGNETS ARE ATTACHED IN THE
ROTOR AND MOVE THE ELECTROMAGNETS TO THE
STATOR.
• THE HIGH POWER TRANSISTORS ARE USED TO
ACTIVATE ELECTROMAGNETS FOR THE SHAFT TURNS.
• THE CONTROLLER PERFORMS POWER DISTRIBUTION BY
USING A SOLID-STATE CIRCUIT.

5. BRUSHLESS SOLUTION TO REMOVE
COMMUTATOR‘S
• THE DEVELOPMENT OF SEMICONDUCTOR ELECTRONICS IN THE 1970S ALLOWED THE
COMMUTATOR AND BRUSHES TO BE ELIMINATED IN DC MOTORS.
• IN BRUSHLESS DC MOTORS, AN ELECTRONIC SERVO SYSTEM REPLACES THE
MECHANICAL COMMUTATOR CONTACTS.
• AN ELECTRONIC SENSOR DETECTS THE ANGLE OF THE ROTOR, AND
CONTROLS SEMICONDUCTOR SWITCHES SUCH AS TRANSISTORS WHICH SWITCH
CURRENT THROUGH THE WINDINGS, EITHER REVERSING THE DIRECTION OF THE
CURRENT, OR IN SOME MOTORS TURNING IT OFF, AT THE CORRECT TIME EACH 180°
SHAFT ROTATION SO THE ELECTROMAGNETS CREATE A TORQUE IN ONE DIRECTION.

6. APPLICATIONS
• NEVERTHELESS, BRUSHLESS MOTORS HAVE COME TO DOMINATE MANY
APPLICATIONS, PARTICULARLY DEVICES SUCH AS COMPUTER HARD DRIVES AND
CD/DVD PLAYERS.
• SMALL COOLING FANS IN ELECTRONIC EQUIPMENT ARE POWERED EXCLUSIVELY BY
BRUSHLESS MOTORS.
• THEY CAN BE FOUND IN CORDLESS POWER TOOLS WHERE THE INCREASED
EFFICIENCY OF THE MOTOR LEADS TO LONGER PERIODS OF USE BEFORE THE
BATTERY NEEDS TO BE CHARGED.
• LOW SPEED, LOW POWER BRUSHLESS MOTORS ARE USED IN DIRECT-DRIVE
TURNTABLES FOR GRAMOPHONE RECORDS.

7. ADVANTAGES OF BRUSHLESS DC MOTOR
1. Brushless motors are more efficient as its
velocity is determined by the frequency at
which current is supplied, not the voltage.
2. As brushes are absent, the mechanical
energy loss due to friction is less which
enhanced efficiency.
3. BLDC motor can operate at high-speed
under any condition.
4. There is no sparking and much less noise
during operation.
5. More electromagnets could be used on the
stator for more precise control.
6. It is high performance motor that provides
large torque per cubic inch over a vast sped
rang.

8. DISADVANTAGES OF BRUSHLESS DC MOTORS
• BLDC MOTOR COST MORE THAN BRUSHLESS DC MOTOR.
• THE LIMITED HIGH POWER COULD BE SUPPLIED TO BLDC MOTOR, OTHERWISE
TOO MUCH HEAT WEAKENS THE MAGNETS AND INSULATION OF WINDING MAY
GET DAMAGED.

9. THANK YOU