A stepper motor is an electromechanical device which converts electrical pulses into discrete mechanical movements. The shaft or spindle of a stepper motor rotates in discrete step increments when electrical command pulses are applied to it in the proper sequence. The sequence of the applied pulses is directly related to the direction of motor shafts rotation. The speed of the motor shafts rotation is directly related to the frequency of the input pulses and the length of rotation is directly related to the number of input pulses applied.
There are three basic stepper motor types. They differ in terms of construction based on the use of permanent magnets and/or iron rotors with laminated steel stators. They are:
- Variable-reluctance, this type of motor consists of a soft iron multi-toothed rotor and a wound stator. When the stator windings are energized with DC current the poles become magnetized. this stepper motor does not use a permanent magnet. As a result, the motor rotor can move without constraint or “detent” torque. This type of construction is good in non industrial applications that do not require a high degree of motor torque, such as the positioning of a micro slide.
- Permanent-magnet, is a low cost and low resolution type motor with typical step angles of 7.5° to 15°. (48 – 24 steps/revolution). Permanent-magnet motors as the name implies have permanent magnets added to the motor structure. It is a relatively low speed, low torque device with large step angles of either 45 or 90 degrees. It’s simple construction and low cost make it an ideal choice for non industrial applications, such as a line printer print wheel positioner.
- Hybrid, this type of motor combine the best characteristics of the variable reluctance and permanent magnet motors, provides better performance with respect to step resolution, torque and speed. Typical step angles for the Hybrid stepper motor range from 3.6° to 0.9° (100 – 400 steps per revolution). Because they exhibit high static and dynamic torque and run at very high step rates, hybrid motors are used in a wide variety of industrial applications.
Get detail information of Stepper Motor Winding and Wiring Diagram here:
Stepper Motor Basics – Link (PDF file, source: www.solarbotics.net)
Stepper Motor System Basics – Link (PDF file, source: www.ams2000.com)
Stepper Motor Wiring – Link (source: www.piclist.com)