In this article we will know about the types of stepper
motor and also know about the application of stepper motor and their advantage.
Stepper Motor
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.