working of stepper motor

  Introduction of stepper motor:-

A stepper motor is a brushless dc motor and the stepper motor rotor rotates in discrete angular displacements when its stator windings are energized in a sequence programmed manner. stepper motor Rotation possible because of magnetic field interaction between rotor poles and stator poles of the sequentially energized field winding. The rotor doesn't consist of any electrical windings but has a rotor consist salient and magnetic/or magnetized poles.

The stepper motor is a digital actuator its input is in the form of digital signals and its output is in the form of discrete angular rotation. The angular rotation is dependent on the number of input pulses to the motor is suitable for controlling the position by controlling the number of input pulses. Thus they are identically suited for an open position and speed control.

Applications

   

• Graph plotters
•  Tape driver
•  Disk Drives
•  Machine Tools 
•  IC Fabrication and Electric Watches
• Robotics space Vehicle
• X-Y Recorders 
•  Printers

Types of stepper motor 

On the basics of construction, stepper motors may be divided into two major groups.

 1. Without Permanent Magnet (PM)

 (a) Single Stack

 (b) Multi Stack

 2. With Permanent Magnet 

(a) Claw Pole Motor 

(b) Hybrid Motors

Working of stepper motor

Position -1

The stepper motor moves toward the low reluctance path when pole-1 and pole-2 energized stepper motor rotor tends to low reluctance.

                                                         

 

Position -2

when stator pole-2 and pole-4 energized rotor again follow low reluctance path means rotor moves 90 forward.

                                            

                                                            

Position -3

when stator pole-1 and pole-3 energized rotor again follow low reluctance path means rotor moves 180 forward.

                                            

Position -4

when stator pole-2 and pole-4 energized rotor again follow low reluctance path means rotor moves 270 forward.

                                          

Position -5

when stator pole-1 and pole-2 energized rotor again follow low reluctance path means rotor moves 360 forward.

 This five-step process do again and again stepper motor moves continuously. This is a complete working of stepper motor.