Vacuum stepper motor

Stepper motor, also known as pulse motor, is based on the most basic principle of electromagnet. It is a type of electromagnet that can rotate freely, and its operating principle relies on the change of air gap magnetic conductivity to generate electromagnetic torque. Its original model originated between 1830 and 1860. Around 1870, attempts were made to control the electrode delivery mechanism of hydrogen arc lamps. This is considered to be the original stepper motor. In 1923, James Weir French invented the three-phase variable reluctance type, which was the predecessor of the stepper motor. At the beginning of the 20th century, stepper motors were widely used in telephone automatic exchanges. Due to the competition for colonies among Western capitalist powers, stepper motors were widely used in independent systems such as ships and airplanes that lacked AC power. In the late 1950s, the invention of transistors gradually applied to stepper motors, making digital control easier. After the 1980s, due to the emergence of low-cost microcomputers in a multifunctional manner, the control methods of stepper motors became more flexible and diverse. [2]
The biggest difference between a stepper motor and other control motors is that it receives digital control signals (electrical pulse signals) and converts them into corresponding angular or linear displacements. It is itself an executing element that completes digital mode conversion. Moreover, it can achieve open-loop position control by inputting a pulse signal to obtain a specified position increment. Compared with traditional DC control systems, this so-called incremental position control system has significantly reduced costs and almost no need for system adjustments. The angular displacement of a stepper motor is strictly proportional to the number of input pulses, and is synchronized with the pulses in time. Therefore, as long as the number, frequency, and phase sequence of the motor windings are controlled, the desired angle, speed, and direction can be obtained.