Stepper Motor

Abstract

A General information on stepper motors Stepper motors are special versions of the synchronous machine, in which the rotor is a permanent magnet, while the stator consists of a coil package. In contrast to synchronous motors, stepper motors have a large number of pole pairs. Motor operation requires a control unit, which energises the individual motor windings based on a certain pulse sequence. A stepper motor has a tendency to mechanical oscillation. Above its load limit it loses dynamic characteristics and may lose individual steps. Under high load the shaft may even stop. Safe positioning is therefore only guaranteed within the performance limits. If the motor is operated within its load limits, positioning without feedback of the rotor position can be achieved by linking individual steps. This operating mode (open loop control) and the durability of the stepper motor enable it to be used as a positioning drive in price-sensitive applications.