Difference Between AC Motor And DC Motor

Difference Between AC motor and DC motor

Hello friends, today we are going to talk about the difference between the AC motor and the DC motor.

An electric motor is a machine that converts electric energy into mechanical energy. As the supply is supplied to the input terminal of the motor, the motor produces a certain torque according to its characteristics according its output.

The main function of the AC motor and DC motor is to convert electric energy into mechanical energy.

There are 3 main differences that we will discuss today:

1. The Main Difference Between The Two is The Power Source:

  • An alternating current is given in the AC motor, while a direct current is given in the DC motor.


2. The Second Main Distance Is a Brush:

  • A carbon brush is used inside a DC motor, while no such brush is used in an AC motor.


  • This raises a question in your mind that the brush is also used in the AC sleep ring motor.
  • But let me tell you that there is a big difference between the brush used in an AC sleep ring motor and the brush used in a DC motor.

Also Read : What are the Various Losses in DC Machine | Types Of Losses in DC Machine

Apart from this, one thing to keep in mind:


  • The efficiency of the DC motor is low, while the efficiency of the AC motor is high. As you mentioned above, DC motors have brushes that wear out over time and need to be replaced periodically. So it can be said from this that the maintenance of the DC motor is more.
  • Due to this, the efficiency of the DC motor decreases.

Also Read : What Is Motor Winding | Types Of Motor Winding | Motor Winding Calculation

3. The Third Major Difference is Speed Control:

  • The speed of the AC motor can be easily changed with the help of frequency, while in the DC motor, the current of the armature has to be increased or decreased to increase or decrease the speed.

Apart from this, the following differences are made based on its characteristics.

Characteristics AC Motor (Induction) DC Motor
Supply Operates on AC supply Operates on DC supply
Starting Single Phase requires starting torque, but in 3 phase, there is no such requirement. Self-starting
Supply system Available in single-phase and 3 phase Only a Single Phase is available
Speed control Speed can be changed depending on the frequency Speed  can be changed depending on the armature winding
Brushes & Commutator This type of motor has a long life as it does not have a brush or commuter. Having a brush and commutator reduces the speed and also shortens the life of the motor.
Load change Gives a slow replay Gives a fairly quick replay
Maintenance Requires less maintenance More maintenance is required

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Hey, I am Vishnu Patil and I'm an Electrical Engineer and Electrical maestro. I have more than 10 years of experience with electricals. Through ElectricalGang I want to spread my knowledge with everyone else.

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