The Difference Between DC and AC Motors

Looking for a new motor?

It’s important to know the difference between DC and AC motors before you make your purchase.

While DC and AC motors perform the same function, there are some critical distinctions to keep in mind.

Read on to learn more.

Power source

AC motors rely on an alternating current (A.C.) for their power. This involves an electric current that changes back and forth over time.

On the other hand, DC motors use a direct current power source (D.C.) in order to operate. Direct current power sources include batteries, solar cells, and DC power converters.

AC motors require external assistance in beginning their operation. DC motors can start on their own.


There are two different types of AC motors: Induction and synchronous motors.

Induction AC motors rely on an induced current while synchronous AC motors rotate at supply frequency.

AC motors can be single or three phase.

There are also two types of DC motors: a DC motor with brushes, and one without brushes.

All DC motors are single phase.

Construction and Maintenance

An AC motor incorporates a stator and rotor and several other components.

Because AC motors do not require brushes, they don’t necessitate a lot of maintenance.

DC motors are commutated mechanically. This means that they require more maintenance than AC motors.

Life Expectancy and Cost

AC motors are, in general, built to last. They are tough, industrial motors that can withstand rugged conditions.

These motors are also designed to provide power over longer stretches of time.

DC motors require more maintenance and generally have shorter life spans than their AC counterpart.

DC motor parts can be expensive to replace once damaged or worn down.

As a result, DC motors tend to not be as cost-effective as an AC. AC motors are generally inexpensive and outlast DC motors in performance and durability.

Speed Control

DC motors have the advantage of external speed control. This is especially useful in situations where the motor speed needs to be monitored externally.

An AC motor’s speed is controlled by changing its frequency.

Application and Use

DC motors are still really useful for a variety of industrial purposes. This includes paper and steel mill machines.

AC motors are ideal for any industrial application that requires high and extended power performance.

An AC motor can operate in multiple situations and does not depend upon the quality of the power current or its flow.

These motors are used for more general purposes than DC motors. They are starting to take over the motor market as a more durable and long-lasting motor.

The Takeaway on the Difference Between DC and AC Motors

The basic difference between AC and DC motors is in their source of power. These motors are also built differently and have very distinct life expectancy.

If you are deciding between a DC or AC motor, it’s important to keep in mind what you intend to use your motor for, and what type of performance you are seeking.

AC motors tend to be more durable and cost-effective, in comparison to DC motors.

Still undecided? We can help you find one that suits your industrial needs.

Posted in Motors.