In this article we will know about the types of stepper motor and also know about the application of stepper motor and their advantage.
A stepper motor is a brush less dc motor whose motor rotates in discrete angular increments when its stater winding are energized in a programmed manner. In other words, a stepper motor is a digital actuator whose input is in the form of programmed energization of the stater winding and whose output is in the form of discrete angular rotation. There are a number of different type of motors available and each has its own advantages and disadvantage.
Stepper motor may be divided into the following groups as far as their construction is concerned.
Types Of Stepper Motor
1. Variable reluctance type stepper motor
2. Permanent magnet type stepper motor
3. permanent magnet hybrid type stepper motor
1. Variable reluctance (VR) stepper motor
In this types of stepper motor there is no permanent magnet either on the stater or on the rotor. The stater and rotor are of salient pole type and mode of soft iron stamping.
The stater has a number of wound poles but the rotor has no winding and is cylindrical. The number of poles on the stater is an even multiple of the number of phases for which the stater winding are wound. The number of phases on the stater must be at least three for bidirectional control of the stepper motor.
Application of (VR) stepper motor
Variable reluctance stepper motors are quite inexpensive and suitable for light duties such as those in computer and industrial instrument systems.
2. Permanent magnet (Bipolar) stepper motor
A two-phase bipolar stepper motor has two coils A and B which are wound around the upper and lower halves of stater. the stater surrounds a rotor that contains specifically aligned permanent magnets. The no. of steps per revolution is determined by the no. of pole pairs on the rotor and stater.
The maximum torque with which the excited motor can be loaded without causing a continuous rotation is termed the stepper motor holding torque.
Application PM types of stepper motor
This motor is used as a paper feed motor of a printer or head drive motor of a floppy disk drive.
3. Hybrid types of stepper motor
The hybrid types of stepper motor uses the principle of permanent magnet and variable reluctance stepper motors. In the hybrid motors,the rotor flux is produced by the permanent magnet and is directed by the rotor teeth to the appropriate parts of the air gap. The permanent magnet is placed in the middle of the rotor. It is magnetized in the axial direction. Each pole of the magnet is surrounded with soft toothed lamination.
Advantage of Hybrid stepper motor
The main advantages are hybrid types of stepper motor
1. very small step angles up to 1.8 degree
2. Higher torque per unit volume which is more than in case of variable reluctance motor.
3. Due to permanent magnet, the motor has some definite torque which is absent is( VR) motor.
Hence these are types of stepper motor if you will find any incorrect in above article you must comment below in comment box.
If you want to know more about the types of stepper motor you can also watch this video.