1

definition

An AC motor can be defined as an electric motor driven by alternating current (AC).

A DC motor is a rotating electric motor that converts direct current (direct current energy) into mechanical energy.

2

type

There are two main types of AC motors: synchronous AC motors and induction motors.

There are also two main types of DC motors – brushed DC motors and brushless DC motors.

3

Current input

AC motors only run on input AC power

A DC motor only operates when DC power is supplied. For DC series motors, the motor may run on AC power. However, with parallel motors, the motor is never run on AC power.

4

Commutator and brushes

There are no commutators and brushes in AC motors.

There are commutators and carbon brushes in the DC motor.

5

Input power phase

AC motors can operate on single-phase and three-phase power.

DC motors can only operate on single-phase power.

6

Motor starts

Three-phase AC motors are self-starting, but single-phase AC motors require a starting mechanism.

DC motors are always self-starting in nature.

7

Armature characteristics

In an AC motor, the armature is stationary while the magnetic field rotates.

In a DC motor, the armature rotates while the magnetic field remains stationary.

8

Input terminal

In AC motors, there are three input terminals (RYB).

In a DC motor, there are two input terminals (positive and negative).

9

speed control

The speed of an AC motor can be changed by changing the frequency.

For DC motors, the speed can be controlled by changing the armature winding current.

10

load change

AC motors respond slowly to load changes.

DC motors exhibit a rapid response to load changes.

11

life expectancy

Since AC motors have no brushes and commutators, they are very tightly assembled and have a high life expectancy.

The brushes and commutator in a DC motor limit speed and shorten the motor's life expectancy.

12

efficiency

AC motors are less efficient due to induced current losses and motor slip.

DC motors are highly efficient because there are no slip or induced current losses.

13

maintain

AC motors require less maintenance due to the absence of brushes and commutators.

DC motors require excessive maintenance due to the presence of brushes and commutators.

14

Application areas

When high speed and variable torque are required, AC motors are used.

When variable speed and high torque are required, a DC motor is used.

15

the real function

They are mainly used in large industries. For example: water heater, lawn, garden equipment, etc.

They are mainly used in small household appliances. For example: electric wheelchairs, handheld sprayers and pumps, coffee machines, off-road equipment, etc.