steppermotor

Steppermotor, also known as a stepper motor, is a brushless electric motor that converts digital pulses into precise angular rotation. The motor moves in discrete steps, so a fixed number of pulses yields a fixed rotation. This enables accurate positioning and repeatable motion without requiring feedback in many applications. Stepper motors are commonly used in open-loop control systems and can hold torque when stopped.

Construction and principle: A stepper motor typically has a rotor with permanent magnets or a toothed iron core and a stator containing multiple windings arranged in phases. Energizing windings in a predefined sequence creates a rotating magnetic field that aligns the rotor with successive stator poles. Designs are categorized as permanent-magnet (PM), variable-reluctance (VR), or hybrid stepper motors. Hybrid types combine PM features with reluctance principles and are common for higher torque and finer step resolution. Typical step angles are 0.9°, 1.8°, or larger increments.

Drive and control: Step sequences are generated by a motor driver. Full-step mode advances the rotor by one step per pulse; half-step and microstepping modes interleave sub-steps to achieve smoother motion and higher effective resolution. Torque is highest at low speeds and decreases as speed increases; torque ripple and resonance can affect performance. Most steppers operate in open-loop systems, but closed-loop variants with feedback encoders are available for higher reliability.

Applications and performance: Steppermotors are valued for precise positioning, good holding torque, compact size, and straightforward drive electronics. They are widely used in 3D printers, CNC machines, robotics, camera autofocus mechanisms, automated equipment, and medical devices. Limitations include reduced efficiency at high speeds, audible noise, and the need for appropriate heat management; for high-performance positioning, servo systems with feedback may be preferred.