Types of AC Motors

Updated: May 19, 2023 1:23 PM
what type of motor is used in air conditioner

Whether you have a budget model or a top-tier air conditioner with the latest technology, you’ll find there are multiple types of AC motors inside the unit that create operational efficiency. These separate motors use electrical energy to propel cool air into your home. In addition, a wide range of HVAC motors affects the energy consumption of the air conditioner system. If you want to explore what type of motor is used in an air conditioner, read on.


  • Air conditioners use a variety of motors throughout the unit to cool your home.
  • The most common electric AC motor is a split-phase motor due to the high starting torque.
  • Your AC unit needs all the electric motors to maintain absolute efficiency while working.

Insider Tip

You should contact a qualified HVAC professional if you suspect a faulty compressor motor.

What Types of Motor Do AC Units Use

If you know what an air exchanger is in air conditioning, you understand how critical electric motors are for an energy-efficient system. For a basic breakdown, an air conditioner’s motor is composed of a stator and rotor. A stator remains stationary while the electrical rotor rotates inside the stator. The rotation induces an electric current and thus a magnetic field. With the rotor being attached to the motor shaft, the shaft then rotates as well to power the machine. Keep in mind that motors can also be a source of multiple issues. For example, if the AC makes a loud noise when starting, or a hissing AC unit or an air conditioner knocking noise, the AC motors might be a factor. If you’re repairing the unit at home, you should also learn the kinds of oil for an air conditioner. The single-phase induction motor is one of the simplest types of motors that are used today and is split into two main types, shaded-pole, and split-phase, which is expanded upon below. These types of motors are used in a wide variety of applications and are common in some light industrial purposes as well as household items, like small pumps and ceiling fans.

Split-Phase Motor

This motor type is considered a star player in the HVAC industry due to the high starting torque. Two common types of split-phase motors are capacitor-start-induction-run and resistance-start-induction-run electric motors.

Capacitor Start

Capacitor-start electric motors use a start capacitor to enhance the starting torque. Most of these units disconnect the start capacitor from the start winding circuit when the motor reaches 70 to 80 percent of motor speed using a centrifugal switch.

Resistance Start

A resistance-start electric motor uses a start winding and a run winding that are out of phase by 45 to 90 degrees to boost the startup. This motor uses a centrifugal switch to drop the start winding from the electric circuit.

PSC Motor

Permanent split capacitor (PSC) electric motors are used for various applications like refrigeration and air conditioning compressors. This motor type has high operational efficiency for air conditioning compressor applications, thanks to the separated start and run capacitors. In addition, this electric motor is single-phase and can work in a clockwise or counter-clockwise direction.


Never work on an AC motor without disconnecting it from power because you may suffer an electric shock.

Shaded-Pole Motor

The HVAC industry generally uses shaded-pole motors for low-power applications where high torque isn’t needed. For example, the fan motor in your AC unit is a shaded-pole motor.

STAT: According to a 2020 US EIA (Energy Information Administration) survey, 22% of Americans have air conditioning but do not use a central AC system. (source)

What Type of Motor Is Used in an Air Conditioner FAQs

Can an air conditioner run on a battery?

While your car or RV can run an air conditioning motor from a battery, you cannot run a home AC system from a primary battery. Due to the high power consumption of an AC unit, you would need a home generator to cool your home for a significant period.

Is your house AC or DC?

When you plug an appliance into your wall, you use an alternating current (AC). Direct current (DC) is much more dangerous than AC, but any electronic device that uses a battery power source uses DC. Companies provide an AC adapter to charge phones and other battery-powered devices.

How do electric motors work?

Electric motors convert an electric current into mechanical energy to create the starting torque. The motor circuit uses a magnetic field, and the alternating (AC) or direct current (DC) interacts to generate movement and motor power. While initially meant for low-power applications, modern electric motors can power an air conditioner or electric car.

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