Let's take a look at the specific components of a stepper motor:
1. Bearings
Bearings are an important component in modern mechanical equipment. Their main function is to support rotating mechanical parts, reduce the coefficient of friction during movement, and ensure rotational accuracy. While their literal meaning is "support," this is only part of their function; support essentially means bearing radial loads. They can also be understood as fixing the shaft. (Bearing selection information is available in Quick & Easy Automation.) They fix the shaft, allowing only rotation, while controlling its axial and radial movement. A motor cannot function without bearings. The shaft can move in any direction, but a motor requires only rotation. Theoretically, transmission is impossible. Furthermore, bearings can interfere with transmission. To reduce this impact, high-speed bearings require good lubrication. Some bearings are pre-lubricated, while most require lubricating oil. At high speeds, friction not only increases energy consumption but also easily damages the bearing. The idea of converting sliding friction to rolling friction is incomplete because there are bearings called sliding bearings.
2. Rotor
A rotor is a rotating body supported by bearings. Objects without their own axis of rotation, such as optical discs, can be considered rotors when rigidly connected or equipped with an additional shaft. When the main rotor rotates at high speeds, the shaft undergoes deflection deformation as its speed approaches its critical speed. Resonance can even cause mechanical damage. The natural frequencies of the rotor's lateral vibration are multi-order, and therefore its corresponding critical speeds are also multi-order. When the rotor's operating speed is below the first critical speed, it is called a rigid rotor, while when the rotor's operating speed is above the first critical speed, it is called a flexible rotor.
The operating speed of any type of rotor must not approach its critical speed. The magnitude of the critical speed of a rotor depends on factors such as its manufacturing materials, structural form, geometric dimensions, and support characteristics.
3. Stator
The stator is the stationary part of an electric motor or generator. It consists of three parts: the stator core, the stator windings, and the frame. The stator generates alternating current, while the rotor creates a rotating magnetic field. The stator is the stationary part of an electric motor. It consists of three parts: the stator core, the stator windings, and the frame. The stator generates alternating current, while the rotor creates a rotating magnetic field. The stator consists of the frame, the stator core, the coils, and other structural components that hold these parts in place. The frame is used to secure the core; in a suspended generator, the frame bears the entire weight of the rotating parts. The core is part of the generator's magnetic circuit; and the coils form the generator's electrical circuit.
The stator core is the main magnetic circuit of the stator and also serves as the mounting and fixing component for the stator windings. The stator core consists of components such as sector-shaped laminations, ventilation slots, toothed pressure plates, tension bolts, support blocks, and positioning ribs. There are two stator connection methods: a 4-wire type, where the rotor is connected in series between two stator windings; and a 2-wire type, where the two stator windings are connected first, then connected in series with the rotor (by connecting the two diagonal leads together in the 4-wire type). The two connection methods are different but interchangeable. There are two lead wire methods: one is led out with flexible wire; the other is led out via connectors on the frame, in which case the frame must be retained during winding.
