Points of Difference
AC Motor
DC Motor
Current Input
When an alternating current (AC) is passed as an input, then only the AC motor works.
Dc operates when Direct Current supply is provided. The motor might operate with AC power supply in the DC series motor. However, for shunt motors, DC supply is necessary.
Motor Starting
A single-phase AC motor needs a starting procedure. However, a three-phase AC motor requires no starting mechanism as it is self-starting.
It’s the main difference between AC and DC motors that later one is always self-starting.
Input Terminals
Three input terminals are present in these motors.
Two input terminals that are; positive and negative exist in DC motors.
Types
There are two types of AC motors, i.e., Synchronous AC motors plus Induction AC motors.
There are mainly two types of DC motors, namely; DC motors with brushes and without brushes.
Armature Characteristics
The armature is fixed in this type of motor, and the magnetic field rotates.
The magnetic field remains constant, and the armature rotates in DC motors.
Load Change
To the variable load, these motors don’t show a fast response.
AC DC motor difference is that DC motors show a rapid response to the load change.
Commutators
AC motors don’t contain commutators.
DC motors comprise commutators.
Brushes
Like commutators, brushes are also absent in these motors.
These motors involve carbon brushes.
Life Expectancy
Due to the absence of commutators and brushes, AC motors have a high life expectancy.
The presence of commutators as well as brushes restricts the speed of these motors. Hence, it lessens the life expectancy of the DC motor.
Speed Control
By changing the frequency, it’s easy to change the speed of an AC motor.
By varying the armature winding current, it’s easy to control the speed of DC motors.
Maintenance
Due to the nonappearance of commutators and brushes, AC motors require low maintenance.
Due to the presence of commutators and brushes, DC motors require high maintenance.
Input Supply Phases
These motors can work on both single and three-phase supplies.
DC motors work only when there is a one-phase supply.
Applications
Whenever there is a requirement for rapid speed or inconstant torque, these motors are preferable.
When there is a requirement for changing speed or high torque, these motors are preferable.
Uses
AC motors are commonly used in bulky industry productions.
DC motors are commonly used in minor domestic purposes.
Efficiency
The efficiency of AC motors is often less. It’s because of the motor slip and induction current loss.
There is not any loss in the induction current or magnetic slip. Hence, DC motors have high efficiency.