1. STEPPER MOTOR A stepper motor is a “pulse- driven” motor that changes the angular position of the rotor in “steps”

2. TYPES OF STEPPER MOTOR  VARIABLE RELUCTANCE STEPPER MOTOR  PERMANENT MAGNET STEPPER MOTOR  HYBRID STEPPER MOTOR

3. VR STEPPER MOTOR

4. Variable Reluctance ( VR) stepper motor  Wound Stator poles Single Stack Multiple Stack – smaller step angle  Rotor poles – ferromagnetic material  Direction – stator current polarity  Reluctance of the magnetic circuit formed by rotor and stator teeth varies with angular position of the rotor

5. Modes of operation –VR type  1-phase ON – full step operation  2-phase ON  Half-step – alternate 1-phase & 2-phase mode  Micro stepping

6. 1-PHASE ON – FULL STEP OPERATION

7. 2-PHASE ON MODE

8. HALF-STEP – ALTERNATE 1-PHASE & 2-PHASE MODE

9. HALF STEP OPERATION

10. VR – MULTI STACK

11.  Stepangle β = ((Ns-Nr)/Ns*Nr) *360= 360/m*Nr N s – No. of Stator poles (teeth) N r – No. of Rotor poles (teeth) m - No. of stator phases  Resolution = No. of steps/revolution = 360 o /β

12. THANK YOU