Stepper Motors

Stepper motors are brushless, synchronous electric motors which convert digital pulses into mechanical shaft rotations. With the motor, multiple coils are organised in groups called phases. Each phase is energised in turn causing the motor to rotate in steps. The motor is sent a pulse for each step and can be commanded to move or hold one of the steps. This stepping characteristic allows for very precise positioning and/or speed control. Such motors have torque ratings, which is a measure of their strength. Stepper motors are categorised according to their motor sizes, the gearing, shaft style and wiring coils. The difference between unipolar and bipolar stepper motors is the varying voltage levels. There is also a multi-phase version which has lower levels of vibration. The most common types of stepper motors are the permanent magnet stepper, the hybrid synchronous stepper and the variable reluctance stepper. Stepper motors have a number of applications. In industry, they can be used for mechanised machinery such as packaging machines. For computer hardware, stepper motors can be found in floppy and hard disk drives and printers. They are also present in slot machines, image scanners, CD drives and camera lenses.