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- 1. STEPPER MOTOR J. BelwinEdward Assistant Professor Senior School of Electrical Engineering VIT University Vellore
- 2. Applications Computer peripherals Textile industries ICfabrications Robotics Applications requiring incremental motion Typewriters Line printers Tapedrives Floppy disk drives Numerically-controlled machine tools Process control systems X-Y plotters
- 3. Applications contd…. •Commercial, militaryand medical applications •Mixing, cutting, striking, metering, blending •Application in manufacture of packed food stuffs •Application in manufacturing of commercial end products •Production of science fiction movies.
- 4. Step Angle -β • As small as 0.78o to 90o • Most commonly used – 1.8o, 2.5o, 7.5o, 15o β = (Ns-Nr) x 360o = 360o Ns.Nr mNr Ns – No. of Stator poles (teeth) Nr – No. of Rotor poles (teeth) m - No. of stator phases
- 5. Resolution • Resolution =No. of steps/revolution = 360o/β
- 6. Types • Variable Reluctance- VR • Permanent Magnet - PM •Hybrid
- 7. VR, PM andHybrid types
- 8. 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
- 9. Variable Reluctance steppermotor Single Stack
- 10. VR – Multistack
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- 12. Modes of operation–VR type • 1-phase ON – full step operation • 2-phase ON • Half-step – alternate 1-phase & 2-phase mode • Micro stepping
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- 17. Permanent Magnet steppermotor • Wound Stator poles – Single Stack – Multiple Stack – smaller step angle • Rotor poles – permanent magnet • Rotor Shape - Cylindrical • Direction – stator current polarity
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- 20. Modes of Operation– PM type • 1-phase ON mode • 2-phase ON mode • Half step mode
- 21. Modes of Operation– PM type
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- 23. Hybrid stepper motor •Combination of VR and PM • Wound Stator poles – (similar to VR) – Single Stack – Multiple Stack – smaller step angle • Rotor poles – permanent magnet • Rotor shape – not Cylindrical • Direction – stator current polarity