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The Difference Between Types of Electric Motors: AC or DC

The Difference Between AC and DC Electric Motors

Both AC and DC electric motors serve the function of converting energy from electrical to mechanical. However, they are powered, controlled, and constructed using different technologies and engineering approaches. In this article, we will help you to pick the best electric motor service San Diego can offer by taking a deeper look at the differences between these two types of electric motors. After all, it takes more than working knowledge to make an informed decision and only top specialists have the expertise to help you choose the best course of action: repair or replace.

What exactly is an AC motor and how does it operate?

AC motors are usually ran by an AC variable frequency drive. They work by applying alternating current (AC) to the electric motor. An AC motor's main parts are the stator and the rotor.

An AC motor stator supplies alternating current to the coils inside of it and in doing so generates a rotating magnetic field. The rotor, as its name implies, rotates inside the electric motor's coils and is connected to the output shaft that creates torque by the rotating magnetic field. There are two types of AC motors - the induction motor and the synchronous motor.

Induction Motors vs Synchronous Motors

An induction motor utilizes a magnetic field on the rotor that's produced by an induced current. A synchronous motor, on the other hand, either rotates exactly at the supply frequency or at the sub-multiple of the supply frequency. A synchronous motor is therefore capable of operating with precision supply frequency because it doesn't need induction, and because its magnetic field is created by a current delivered through a permanent magnet or through slip rings. Synchronous motors, therefore, work faster than induction motors because their speed is reduced by the slip of the asynchronous motor.

A closer look at DC motors and what makes them unique

Like their name implies, DC motors are powered using direct current (DC) and are among the types of electric motors that count as mechanically commuted machines. DC motors contain a voltage induced rotating armature winding, as well as a non-rotating armature field frame winding that is a permanent magnet, or a static field.

They utilize different motor connections of the field and armature winding to generate different torque regulation and speed. Unlike AC electric motors, DC motor speed can be controlled from inside the winding by adjusting the field frame current, or regulating the voltage applied to the DC electric motor armature.

The majority of DC motors produced today are designed to be controlled through industrial electronic DC drives. Their main use is in larger machinery such as steel mill rolling machines or paper producing machines.

Which of these two types of electric motors is right for you?

AC motors are often used in applications where power performance is needed for longer time periods. Conversely, DC motors are often encountered in applications where the motor speed has to be externally controlled. All DC motors are single-phase motors, whereas AC motors can be either a single or three-phase motor. Combining an AC motor and drive is the most cost-effective choice for most applications.

#1 Diesel and Electro-mechanical Repair Contractor

Do you have any further questions about these two types of motors? Here at PCE, we have over 40 years of experience working with electric motors and generators as well as diesel engines. We offer turnkey solutions to our clients, among which is the US Navy. Let us show you our expertise. Feel free to give us a call!

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