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AC and DC Motors: What You Need to Know

Do you know the difference between AC and DC motors?

If you’re shopping for motors, it’s helpful to know how each one works so you can decide what’s best to meet your needs. That’s why we’ve put together this essential guide to help you learn the difference between AC and DC.

Read on to find out what you need to know!

AC and DC Motors: A Short Guide

Most motors are either direct-current (DC) or alternating-current (AC). Let’s take a look at the basic difference between the two types of motors.

The essential difference between the two motors is right there in the name. AC motors use an alternating current to change electrical energy into mechanical energy. DC motors use direct current to achieve the same goal.

However, there are more detailed differences in the way each type of machine operates depending on its power source. Let’s take a closer look at what those are.

DC Motors: The Details

DC motors usually use a system of carbon brushes plus a commutation ring to change the current’s direction using a rotating armature. Fixed magnets inside the motor interact with an internal rotor to get the motor to turn.

Because of the carbon brushes, DC motors tend to have more limited lifespans. Most can last for about 1,000 to 1,500 hours, but if under a heavy load they may last for as little as 100 hours or less.

In ideal conditions, DC motors can operate much longer, though. These motors are very efficient, and lose efficiency only in a few specific areas. The winding and friction of the brushes are two places where these motors lose efficiency.

AC Motors: The Details

The AC induction motor, a common type of AC motor, uses a system of coils that get their power from the AC input voltage. This input voltage creates a stator field, which in turn induces the rotor field.

Another kind of AC motor, the synchronous motor, works using precision supply frequency. This kind of motor uses a current from either permanent magnets or slip rings to create a magnetic field.

AC synchronous motors are faster than AC induction motors because the induction motor’s speed is slowed down by the lack of synchronization.

AC motors are designed to operate according to a performance curve that aligns with the motor’s greatest efficiency. If the motor operates at a different point on the performance curve, efficiency will be lost.

Because AC motors need to use extra energy to create a magnetic field, they operate less efficiently than DC motors.

AC and DC Motors: What’s Best for You?

Both of these motor types operate differently and have a different performance. Depending on the task at hand, one kind of motor may be right for the job.

When you need to have external control of the motor speed, DC motors are usually best. However, AC motors are ideal when you want a strong performance for a longer period.

You should also consider wear and tear, and the cost of replacement parts. An electric DC motor will usually have more moving parts that are more costly to replace. For cheaper repairs, you’ll want an AC electric motor.

Need to buy the perfect motor for the job? We’ve got what you need! Check out our selection here.

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