1. STEPPER MOTOR  Introduction  Construction  Operating Principle  Application Prepared By: Nagendra Kumar & Atul Gautam

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3.  Introduction  Steeper Motor: An electromechanical, digitally pulse operated motor which operated and controlled in step by step rotation, is called stepper motor.

4.  Contruction Stepper motor has basic component as Armature core and winding Permanent magnet/soft magnetic iron rotor Auxiliary parts( i.e. cage, bearing, shaft etc.) Controlling switch and voltage source

5. Type Of stepper Motor: 1.Permanent magnet (Rotor) 2.Variable reluctance (Magnetic iron rotor) 2.a. Single Stack 2.b. Multi-stack 3. Hybrid Stepper motor

6. 1. Permanent Magnet (Rotor)

8. Operating principal  we consider A and A’ fed from positive pulse then rotar aline with stator pole.  in the next step give postive pulse to B and B’.  Then rotor start moving in discreate step or some specific angle.  pulses are control by microcontroller.

9.  if we feed the coils with pulses which are periodically repeated the rotor will turn step by step at synchronous speed of rotaion.  the residual magnetism in the permanent magnet material produce detent torque.

10. 2.a. Single stack Variable reluctance

11. Operating principal of single stack Variable reluctance motor  This type of stepper motar employs the principal of minimum reluctance path.  it has 4-phase,4-stator,2-tooth rotor and one variable reluctance.  it is connected with d.c source as shown in figure.  when phase S(A) is excited the rotor aligns with the axis of phase S(A),now switch S(A) off and S(B) switched on the

12. Rotor moves through 90 degree and align with the resultant air gap field which lies along with the phase S(B) and so on the rotar start moving. Step angle = 360/(q*Nr) Where, q = No of Phase Nr = No of rotor teeth Torque = (1/2) * (I*I) * (dL/d θ)

13. 2.b. Multi-stack Variable reluctance

14.  its principal is same as single stack variable stepper motor.  In the given figure it is side view.  In this motor,rotar have a common shaft and stator have a common frame.  it produce more torque.

15. 3. Hybrid Stepper Motor

16. Operating principal and working  it operates on the combined principal of the permanent magnet and varible reluctance stepper motor, so this motor is called hybrid motor.

17. Application  Space-Craft  Military  Electrical watch  Robotics  Line –Printer  Science Fiction Movies

18. Controller for motor

19. Printer

20. Robotics

21. Electric Watch

22. Advantage of PM Motors They have a low power requirements due to presence of permanent magnet in the rotor. Due to use of permanent magnet the rotor has high detent torque.

23. Drawbacks of PM Motors Due to use of large permanent magnet the motor gives a poor torque per unit volume. The step size is relatively large.

24. Thanks