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If DC Has Zero Frequency, How Does a DC Motor Actually Run?

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How Does a DC Motor Work? Working Principle, Types, Applications, and Key Components, like the commutator, are explained. Why is BLDC a replacement for a DC Motor?

That magic is created by a thing called ‘commutator’. 

Commutator principle: 

DC motor commutator working

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Mutually attractive and repulsive forces: 

As shown in the above animation, a simple arrangement of a commutator, when it rotates, sends forward and reverse current through the coil from the battery. A current-carrying conductor generates its own magnetic field. This arrangement creates alternating changing magnetic poles (north/south) in the coil. This magnetic field reacts with the permanent stator magnetic poles to create mutually attractive and repulsive forces to generate circular motion.

Attractive and repulsive forces generated in the DC Motor

A typical commercial commutator and DC motor.

DC Motor Animation

BLDC Motor: 

DC motors are now replaced by BLDC motors, in which the rotor is a permanent magnet and alternating rotating magnetic poles are generated in the stator electronically by switching coils in succession.

BLDC Motor working


BLDC motors you will find everywhere, from computer CPU fans to drones, washing machines, electric cars and now in ceiling fans.

FAQ Set:

Q1: How does a DC motor work?
A DC motor converts electrical energy into mechanical energy. When current flows through the motor’s armature winding, it interacts with the magnetic field, producing a rotational force (torque) that turns the shaft.

Q2: What is the working principle of a DC motor?
The principle is based on the Lorentz force: a current-carrying conductor in a magnetic field experiences a force perpendicular to both the current and the field, causing rotation.

Q3: What are the key components of a DC motor?

  • Armature (rotor): Rotating winding

  • Stator: Provides a magnetic field

  • Commutator: Reverses current in the armature windings to maintain continuous rotation

  • Brushes: Conduct current between the stationary and rotating parts

  • Shaft and bearings: Transmit mechanical motion

Q4: What are the types of DC motors?

  • Brushed DC Motors: Use brushes and a commutator

  • Brushless DC Motors (BLDC): Use electronic controllers instead of brushes

  • Shunt, Series, and Compound motors differ in how field windings are connected

Q5: What are typical applications of DC motors?

  • Electric vehicles and scooters

  • Industrial machinery

  • Household appliances (fans, mixers)

  • Robotics and servo systems

Q6: Why is BLDC replacing traditional DC motors?

  • No brushes: Reduces wear and maintenance

  • Higher efficiency and longer lifespan

  • Better speed and torque control via electronic controllers

  • Less noise and heat generation

Q7: What are the advantages of using BLDC motors over brushed DC motors?

  • More precise and efficient operation

  • Longer operational life due to the absence of a mechanical commutator

  • Suitable for high-speed and high-performance applications

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