1. STEPPERS AND SERVOS

2. Types of stepper motors Based on construction Based on construction Variable reluctance Variable reluctance Permanent magnet Permanent magnet Hybrid Hybrid Based on winding Based on winding Unipolar Unipolar Bipolar Bipolar

3. Variable Reluctance This motor dose not have a permanent magnet This motor dose not have a permanent magnet These motors have four stater pole sets as shown below These motors have four stater pole sets as shown below

4. Permanent magnet These motors have permanent magnet rotor These motors have permanent magnet rotor It is a relatively low speed, low torque device It is a relatively low speed, low torque device It has a large step angle of either 45 or 90 degrees It has a large step angle of either 45 or 90 degrees

5. Hybrid This is a combination of variable reluctance and permanent magnet motors This is a combination of variable reluctance and permanent magnet motors These motors have multi toothed starter poles and permanent magnet rotor These motors have multi toothed starter poles and permanent magnet rotor These motors normally have very small step angle. These motors normally have very small step angle.

6. Bipolar and Unipolar Bipolar stepper comes with 4 wires and have no tapping at the center of the windings Bipolar stepper comes with 4 wires and have no tapping at the center of the windings Unipolar steppers comes with 5,6 or 8 wires. Unipolar steppers comes with 5,6 or 8 wires.

8. Driving a unipolar stepper

10. Servos

11. Driving a servo A servo runs on a PWM signal as shown below A servo runs on a PWM signal as shown below W=1.5 ms for normal position W=1.5 ms for normal position W=1 ms for 0 degree W=1 ms for 0 degree W=2ms for 180 degrees W=2ms for 180 degrees

12. Thank You