Stepper motors are capable of precise motion in increments and convert electronic pulses into proportional mechanical movement. They have a rotor inside a stator with electromagnets that pull the rotor teeth into alignment as different coils are energized, resulting in rotation. There are several types including permanent magnet, variable reluctance, and hybrid. Stepper motors can operate in full or half step modes, rotating the shaft by 90 or 45 degrees respectively with each pulse. They are used in applications like printers, CNC machines, and disk drives where precise positioning is needed.

1. WELCOME

2. STEPPER MOTOR
By
LALKISHORE PRASD
Electrical & Electronics Department

3. Introduction
Capable of motion in precise increments
converts electronic pulses into
proportionate mechanical movement

4. Stepper Motor / Electro magnet

5. Rotor
Stator
Outside Casing
Coils Stator
Rotor
1
N
2 2
S
Internal components of a Stepper Motor
1

6. Cross Section of a Stepper Motor
1 Stators
S
N
2 2
S
N
1
Rotor

8. Types of Stepper Motor
• Permanent Magnet Stepper Motor
• Variable Reluctance Stepper Motor
• Hybrid Stepper Motor

9. Full Step Operation
Four Steps per revolution i.e. 90 deg. steps.

10. Half Step Operation
Eight steps per. revolution i.e. 45 deg. steps.

11. Practical Stepper motor operation
The top electromagnet (1) is turned on, The top electromagnet (1) is turned
attracting the nearest teeth of a gear- off, and the right electromagnet (2) is
shaped iron rotor. With the teeth aligned energized, pulling the nearest teeth
to electromagnet 1, they will be slightly slightly to the right. This results in a
offset from electromagnet 2 rotation of 3.6° in this example.

12. The bottom electromagnet (3) is The left electromagnet (4) is enabled,
energized; another 3.6° rotation rotating again by 3.6°. When the top
occurs. electromagnet (1) is again enabled, the
teeth in the sprocket will have rotated by
one tooth position; since there are 25 teeth,
it will take 100 steps to make a full rotation
in this example.

13. Stepper motor applications
Stepping Motor to move read-write head

14. Stepper motor applications
Paper feeder on printers
Stepper motors
CNC lathes

15. Stator coils
Rotor
CNC Stepping Motor
CNC Stepping Motor

16. Advantages / Disadvantages
Advantages:-
Low cost for control achieved
Ruggedness
Simplicity of construction
Can operate in an open loop control system
Low maintenance
Less likely to stall or slip
Will work in any environment
Disadvantages:-
Require a dedicated control circuit
Use more current than D.C. motors
High torque output achieved at low speeds

17. Control sequence to turn a stepper motor
+
Step 1 0 0 1 1
CW CCW
Step 2 1 0 1 0
Step 3 1 1 0 0
Step 4 0 1 0 1

18. Servo Motor Detail
Actuator
Reduction gear
Position feedback
Potentiometer
+ 5V (closed loop system)
Small electric DC motor