1. Stepper Motor

2. 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Introduction
• Incremental motion machine, does not rotate continuously
• Designed to rotate through a specific angle for each
electrical pulse
• Each pulse initiates the drive circuit to produce 1 step of
angular movement
• Popular types of stepper motor
 Variable Reluctance (VR) type
 Permanent Magnet (PM) type
 Hybrid type (combination of VR & PM)

3. 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Connection diagram

4. 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Construction
• Stator : Slotted, Multi pole, multi phase winding
• Rotor : No winding
• Number of poles depends upon required angular change per input pulse
• Operate with an external drive logic circuit

5. 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Working
• Train of Pulses applied to drive circuit
• Drive circuit supplies currents to the stator winding of motor
• Axis of air gap field coincides with the input pulses
• Rotor follows axis of the air gap magnetic field depending upon pulse rate
• Step Angle
 Angle by which rotor moves when 1 pulse is applied to the stator,
degrees
 Resolution of positioning is decided by step angle
 Smaller the step angle, higher is the resolution
 Higher the resolution, greater is the accuracy of object
positioning
srevolutionrotorofNumber
StepsofNumber
Resolution =

6. 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Applications & Advantages
• Applications
 Use with computer controlled systems
 Machine Tools, Tape drives, Floppy disc drives
 Printers, X-Y plotters, Robotics, Electric Watches, Space crafts
 Science Fiction Movies, Commercial, Medical, Military
Applications
• Advantages
 Compatibility with digital systems
 Precise control of angular displacement without feedback
arrangement
 No requirement of any sensors for position and speed sensing
 Readily interfaced with microprocessors

7. 101 / 102 Basic Electrical Technology Dept of E & E, MIT Manipal
Applications & Advantages
• Applications
 Use with computer controlled systems
 Machine Tools, Tape drives, Floppy disc drives
 Printers, X-Y plotters, Robotics, Electric Watches, Space crafts
 Science Fiction Movies, Commercial, Medical, Military
Applications
• Advantages
 Compatibility with digital systems
 Precise control of angular displacement without feedback
arrangement
 No requirement of any sensors for position and speed sensing
 Readily interfaced with microprocessors