Single Phase Motors

Single Phase Motors (1Ph)

Looking to purchase a single phase motor? We have all types of 230v motors available from stock and can also supply 110v Motors to order. Single Capacitor for low torque starting or Capacitor Start Capacitor Run (Dual Cap) for applications where higher starting loads may be required.

Not sure which single phase motor you might require? Call or email us for technical help.

What is a Single Phase Motor?

A single phase motor uses an oscillating magnetic field created by a rotating pulse to rotate the shaft. Because of this, a single phase motor effectively has zero start up torque. This has been overcome with the help of modern technology and has been used to create several different types of single phase electric motors, all of which are suited to different applications.

What are the different types of single phase motor?

There are two main types of single phase motor.

Single Capacitor - Cap Start

The single capacitor motor sometimes called a 'permanent cap motor' use the capacitor to create a secondary phase. This uses windings spaced 90 degrees apart and pulses to create the rotation.

Once this type of motor reaches operating speed, a centrifugal switch cancels out the extra winding and allows it to run on a single phase. These motors have lower initial startup torque.

Dual Capacitor - Cap Start Cap Run

This is a variation on the previously mentioned cap start motor. This motor is fitted with two capacitors as the name suggests. One is used to create the secondary phase to start the motor, this is usually a larger capacitor which allows for a higher starting torques for applications that require it. The smaller capacitor will then take over to allow for a smoother running motor without torque peaks, but small enough not to draw excessive current and create extra heat.

Single Phase Motor Applications

There are many applications for single phase motors as they usually rely on a 110v or a 230v supply. Since 230v single phase supply's are found mostly in domestic settings and on farms or smaller industrial units, these motors are often used on smaller appliances such as:

• Air compressors
• Blowers
• Fans
• Small Pumps
• Saws
• Air Conditioning Units
• Burner Fans

Single Phase Motor Speed Control

Single Phase motors cannot easily be speed controlled. They can be used with a device known as a Variac, but as there are huge energy losses and the speed control is not very accurate, these are not popular and we do not recommend them.

Should you require a slower running motor, or a variable speed motor, we suggest you opt for a 3 Phase motor used in conjunction with a Variable Speed Drive also known as an AC Inverter. These can be used with a single phase supply up to 4kW.