What is the Difference Between Single Phase and Three Phase Motors?

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Are you interested in electricity? Wondering what the difference is between a single-phase and three-phase motor? You can quench your curiosity by inquiring about the Electrical Applications program at The Refrigeration School (RSI). In as little as seven months, you can become an electrician apprentice and utilize your knowledge of single-phase and three-phase motors for residential and commercial applications.

What is a Motor?

A motor changes energy into mechanical energy to produce motion. There are electric and combustion motors. An electric motor uses magnets to create motion. Two ends of the magnet repel each other creating rotational motion. Electric motors power everything from fans to industrial equipment. So, what is the difference between a single-phase and three-phase motor?

What is a Single-Phase Motor?

A single-phase motor is a two-wire alternating current power circuit that uses a single-phase power supply to convert electric energy into mechanical energy. Single-phase motors commonly power equipment that requires lower horsepower. They power air conditioners, automatic doors, small power tools, fans, pumps, and refrigerators.

What is a Three-Phase Motor?

A three-phase motor uses a three-phase power supply to convert electric energy into mechanical energy. This motor contains three hot wires and one neutral wire and uses three alternating currents. It is more efficient at transmitting a high volume of electricity over a large area. Three-phase motors are commonly used in industrial applications like conveyors, lathes, and pressure and grinding machines.

What is the Difference Between Single Phase and Three Phase Motors?

The difference between a single-phase and three-phase motor1 is that a single-phase motor needs a capacitor to start because it only generates an alternate field. The three-phase motor generates a rotating magnetic field, so it does not need a capacitor.

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Power Usage

The advantage of a single-phase motor is that it uses less power to function. On the other hand, the three-phase motor is more powerful, with a power capacity of 1 ½ times that of the single-phase motor.


The three-phase motor is reversible and can be used as a generator by turning mechanical energy into electrical energy. This means that it can create rotational motion on its own by flipping the polarity of the magnet as if moves from north to south. The flip causes a repelling action that creates a motor’s motion.


Since a three-phase motor can efficiently transmit large amounts of electricity over large areas, it is more economical.


The three-phase motor lasts longer than the single-phase motor, making it more durable and cost-effective.


Since the single-phase motor voltage rate can fluctuate and reduce the consistency of the power supply, the three-phase motor voltage is much more efficient.


Single-phase motors can be noisy, while three-phase motors make less noise when operating. Single-phase motors are used when less power is needed to minimize the auditory noise coming from equipment like an air conditioner.

Want To Learn More?

If you want to learn more about electrical applications and technologies, The Refrigeration School has trade school programs that can equip you with the necessary skills and expertise. Call us today at (602) 607-0024 to learn more about our Electrical Applications program.

  1. https://www.gainesvilleindustrial.com/blog/single-three-phase-motors-guide/