What are Brushless DC Motor?

What are  Brushless DC Motor?

BLDC Motor Definition

A brushless DC motor is defined as an electronically commutated motor that lacks brushes, enhancing operational efficiency and torque.

Core Components

A BLDC motor consists of two primary parts: the rotor (rotating) with magnets, and the stator (stationary) with windings. Permanent magnets on the rotor interact with the stator’s electromagnets, controlled by high-power transistors and a solid-state circuit for power distribution.

Design Types

Inner Rotor Design

In an inner rotor design, the rotor is located in the centre of the motor and the stator winding surround the rotor. As the rotor is located in the core, rotor magnets do not insulate heat inside and heat get dissipated easily. Due to this reason, inner rotor designed motor produces a large amount of torque and validly used.

Outer Rotor Design

In outer rotor design, the rotor surrounds the winding which is located in the core of the motor. The magnets in the rotor trap the heat of the motor inside and do not allow to dissipate from the motor. Such type of designed motor operates at lower rated current and has low cogging torque.

Operational Efficiency

BLDC motors excel in efficiency due to their brushless design, which eliminates friction losses and allows precise speed control.

Advantages

• Brushless motors are more efficient as its velocity is determined by the frequency at which current is supplied, not the voltage.

• As brushes are absent, the mechanical energy loss due to friction is less which enhanced efficiency.

• BLDC motor can operate at high-speed under any condition.

• There is no sparking and much less noise during operation.

• More electromagnets could be used on the stator for more precise control.

• BLDC motors accelerate and decelerate easily as they are having low rotor inertia.

• It is high performance motor that provides large torque per cubic inch over a vast sped rang.

• BLDC motors do not have brushes which make it more reliable, high life expectancies, and maintenance free operation.

• There is no ionizing sparks from the commutator, and electromagnetic interference is also get reduced.

• Such motors cooled by conduction and no air flow are required for inside cooling.

Disadvantages

• BLDC motor cost more than a brushed DC motor.

• Only limited high power should be supplied to a BLDC motor; excessive heat can weaken the magnets and damage the winding’s insulation.