How Does a Stepper Motor Work?

How a Stepper Motor Works

A stepper motor works when the electromagnets in the stator are switched off and on, then the parts of the rotor will be either drawn toward or repelled away from the magnet. This will cause the rotor to rotate in steps, hence the name 'Stepper Motor'. 

The magnets around the edge are also known as poles. In this example, there are four poles which are 90 degrees apart. Opposing magnets are called phases, so this is a two-phase Stepper Motor. Three-phase and four-phase Stepper Motors are also common.

Stepper Motors typically have a defined resolution or number of steps pre-revolution. Most common are 200 steps per rev motors which equate to an individual step size of 1.8 degrees.  Some motors are available with finer resolution at 400 steps per revolution.

Stepper Motors are run by electronic driver modules that can often "micro-step" meaning that full "mechanical" steps can be subdivided whereby hugely increasing the resolution. Typically up to 256 micro-steps per full step resulting in up to 51,200 steps per revolution.

The Construction of a Stepper Motor

To understand how a Stepper Motor works, it is important to understand the construction.

First, there is a rotor, which is the inside of the stepper motor, it is made of two discs which have teeth, and they are similar to gears. One is a magnetic north pole and the other is a south pole. Placing them on top of each other, the teeth will form an alternating pattern of north and south poles.

Round the edge of the rotor, there is, what is called, a stator. This consists of a number of electro-magnets set at equal points around the Rotor. These magnets can be switched off and on, usually in pairs but sometimes individually.

Stepper Motors from Heason Technology

Stepper Motors are one of our most popular products. See our range of Stepper Motors along with our Servo Motors on the Stepper and Servo Motors page of our Website.

If you need any more information on Stepper Motors you can contact us on +44 (0) 1403 792300 or email sales@heason.com.