Differences between AC motor and DC motor, which you can easily tell even within the interview Questions.

Today I will tell you the main  differences between AC motor and DC motor, which you can easily tell even within the interview. (AC motor vs DC motor)

The first difference between AC and DC motors is the power source.

AC motors are powered from Alternating current, but DC motors are powered from Direct current.

Meaning- AC motor runs at alternating current (AC current), while DC motor runs at direct current (DC current).

AC Motor

DC Motor

The second main difference between an AC motor and a DC motor is with the brush.

AC motor does not have a brush and commutator, but DC motor constructed with brush and commutator.

Meaning- Brushes and commutators are fitted inside DC motor, but they are not used inside AC motor.

Here a question may come to your mind that there are brushes inside the AC Sleeping Induction Motor.

There is a huge difference between the slip ring that is used in it and the work of the brush used by the DC motor, both of which are completely different.

The efficiency of a DC motor is low, while the efficiency of an AC motor is better than a DC motor. Because just like I told you that there are brushes inside the DC motor, these brushes get spoiled after some time. And we have to change them from time to time. So you can say that there is more maintenance in the DC motor, due to which the efficiency of the DC motor is reduced.

The third difference between an AC motor and a DC motor is the speed control of the motor.

How to control ac and dc motor speed?

The speed of the AC motor is controlled by changing the frequency. but the speed of the DC motor is controlled by varying the armature winding current.

What is the advantage of DC motors from AC motors?

DC motors have the advantages of high initial torque, fast start and stop, reversing, variable speed with power input, and easier and cheaper to control than AC. The advantages of AC cars include: low power demand at first and small adjustments

• 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 a single-phase supply is 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 is a self-starting motor. 

• 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

Thank You