Hello friends, today I am going to tell you structure and uses of Stepper motor, Permanent Magnet Stepper Motor, working Principle of stepper motor, Stepper Motor Applications: If you also want to know, then keep reading this article completely.
Stepper motor
Stepper motor is also known by other names like-
- stepping motor
- step motor
It is named stepper because it rotates by a fixed angular step in response to the input current received by the controller. Many industrial needs require improved position control of an object or fixed speed control without closed-loop feedback. Stepper motors are used for these purposes. Stepper motors are used in computer equipment to generate driving torque. Because of this, it is developing rapidly.
Structure of Stepper Motor
The structure of the stepper motor consists of two parts.
(i) Stator part (ii) Rotor part
The Stepper motor consists of a slotted stepper in which multipole and multiphase winding are placed. The rotor does not have any windings. It is made of ferromagnetic material or permanent magnet type, or variable reluctance type. The Stepper motor is operated with the help of external drive logic circuit.
A sequence of logic pulses is applied to the input of the drive circuit. Then it gives correct currents to the stator circuit coil, which parallels the axis of the air gap region with the input pulses. Due to which the air gap starts following the magnetic axis according to the rotor pulsator and load torque. For this, either the permanent magnet torque or the reluctance torque is generated in the rotor. The following three types are the most popular rotor arrangements.
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(i) Permanent Magnet Stepper Motor
The stator of a permanent magnet stepper motor is of advanced pole type. In this field, coiling is done. The rotor is made by an advanced pole type permanent magnet and can also be cylindrical.
Permanent magnets are installed on its rotor in axial position as in Figure (a). Therefore, a permanent magnet gives a constant direct current excitation. When energy is supplied to one or more stator coils, the machine behaves like a synchronous motor. The rotor rotates due to attraction or repulsion between the stator and rotor poles.
(ii) Hybrid Stepper Motor
This type of motor has a permanent magnet. Also, a toothed rotor is used. Figure (b) shows a bi-phase, six stepper poles, and six pole hybrid stepper motor.
(iii) Variable Reluctance Motor
In this type of motor, there are no permanent magnets on the rotor, and the rotor is of ferromagnetic multiple tooth type. In this, the torque develops due to the difference between the magnetic reluctance produced between the axes. Its structure is shown in Figure (c).
working Principle of stepper motor
In the Figure, many solenoids are arranged in a circle with an iron bar.
These solenoids are given energy one by one. The magnetic carrying force generated in these reacts with the iron bar, due to which the bar starts rotating and starts acting like a rotor. If energy is given to the solenoids in the order AHGFEDCB, the bar rotates counterclockwise. If power is given to the solenoids in the order ABCDEFGH, the bar rotates clockwise.
The Stepper motor covers an angular distance in one step. It travels a step angular distance for each pulse received in its operating circuit.
For example, let the step angle per pulse of a stepper motor be 7.5°. If a displacement of 225° is required to move an object to a particular position, then the operating circuit of the stepper motor has to give 225/7.5=30 pulses.
Since the rotational speed of a stepper motor depends entirely on the frequency of the step pulse and does not depend on the load, this motor provides a true open-loop speed control plant.
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Stepper Motor Applications
(i) In the recording head of the computer disc drive.
(ii) As a paper feed motor in typewriters and teleprinters.
(iii) To rotate the pen in X-Y graphical plotters.
(iv) NC milling machines, CNC lathe machines, and industrial robots.
(v) Positioning of X-ray tables and satellite solar panels.
what did you learn today:-
structure and uses of Stepper motor, Permanent Magnet Stepper Motor, working Principle of stepper motor, Stepper Motor Applications.