Difference Between AC and DC Motor

Saturday - 24/11/2018 18:24

Difference Between AC and DC Motor

The AC Motor and the DC Motor are differentiated on the various factors like the source or the nature of the power used in the motor.
The commutation process, types, starting of the motor, a number of terminals. Applications of the motor, usage of brushes and the maintenance cost of the motor.

The difference between the AC and DC Motor is given below in the tabulated form


Nature of the Input Current Alternating Current is the main input power in the AC motor Direct Current is the main input power in the DC motor
Supply Sources Three phase or single phase power from the supply mains Energy is obtained from batteries, cells etc.
Commutation Process Absent in AC motor Present in DC motor
Supply Phase Both single phase and three phase supply are used Only single phase supply is used
Number of terminals There are 3 input terminals RYB. There are two input terminals Positive and negative
Carbon brushes No carbon brushes There are carbon brushes in the DC Motor
Applications Suitable for large and industrial applications DC motor is used in small and domestic applications
Starting AC Motor are not self starting. It requires some external starting equipments DC Motor are self starting
Position of Armature The Armature is stationary and the magnetic field rotates Armature rotates while the magnetic field remains stationary.
Maintenance cost Less expensive as compared to DC Motor DC Motor maintenance is more expensive.

In an AC Motor, an alternating current passes through the coils. When an alternating current is passed on the electromagnets is a magnetic field is generated. Stationary parts consist of the electromagnets. The magnetic field which is created changes constantly. The interaction between the electromagnets and the magnetic field makes the motor to rotate.

A Direct current is passed in the stationary part of the motor, which is known as Stator. A Coil of wires which carry an electric current is known as Rotor. A DC Motor converts an electric power into mechanical power.

Difference Between AC (Alternating Current) Motor and DC (Direct Current) Motor

    A C Motor works on the concept of alternating current, whereas DC Motor works of the Direct Current.

    The main source of the AC motor is current coming from the three phase or the single phase supply mains. The sources of the DC Motor are Batteries and Cells.
    In an AC Motor the commutation process is absent hence, there is no use of carbon brushes, whereas in DC Motor the commutation process takes place and thus the carbon brushes are used.

    Both three phase and single phase supply are used in an AC Motor but in DC Motor only single phase supply are used.

    In an AC Motor, there are three input terminals known as RYB (Red, Yellow and Blue). In DC Motor, there are only two terminals. They are known as Positive and Negative.

    AC Motors are not self-starting, and thus, it requires some external equipment to start the motor initially. DC Motor are self-starting motors.

    The Armature is stationary, and the magnetic field rotates in the AC Motor but in DC Motor the armature rotates, and the magnetic field is stationary.

    AC motor is suitable for large and industrial applications whereas DC motors are used for small and domestic applications.

    The maintenance cost of the AC Motor is more as compared to that of a DC Motor.


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