stepper motors

1. Made by:-
Meraj akhtar
EE Dept.
JIT Barabanki

2. CONTENTS
• What Is a Stepper Motor?
• Construction
• Working Of Stepper Motor?
• The 3 Types Of Motors?
• 1. Variable Reluctance Stepper
• 2. Permanent Magnet Stepper
• 3. Hybrid Synchronous Stepper
• Phase Current Waveforms
• Applications

3. Stepper Motor
• Brushless DC electric
motor.
• Division of full rotation.
• Divided to equal steps.
• Motor position
commanded to move.
• Hold at any of steps
without an open loop
controller

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

5. Working
-> 25 teeths
-> 3.6 deg. rotation

6. The 3 Types
Of Motors?
1. Variable
Reluctance
Stepper
2.
Permanent
Magnet
Stepper
3. Hybrid
Synchronous
Stepper

7. Variable reluctance stepper
plain iron rotor
Minimum reluctance
occurs with minimum gap.
Rotor points attracted
towards stator poles

8. One phase on mode full step
A B C 𝜃
A + 0 0 00
B 0 + 0 300
C 0 0 + 600
A + 0 0 900

9. Two phase on mode full step
A B C ANGLE
AB + + 0 15
BC 0 + + 45
CA + 0 + 75
AB - + 0 105

10. Alternate one phase & two phase on
mode,half step operation
A B C ANGLE
A + 0 0 0
AB + + 0 15
B 0 + 0 30
BC 0 + + 45
C 0 0 + 60
CA + 0 + 75
A + 0 0 90

11. Micro stepping
• excitation of two phases simultaneously
as in two phase on operation, but with
one difference.
• current in one phase is held constant at
its maximum, while the current in the
other phase is increased in very small
steps till it reaches its maximum.
• After this further movement of the rotor
is actuated by decreasing the current in
the first phase again in very small steps.

12. Permanent magnet stepper motor
• permanent magnet (PM) in the rotor
• operate on the attraction or repulsion b/w the
rotor PM and the stator electromagnets.
• The motor operates in the following modes of
operation:
• One phase on mode full step operation.
• Two phase on mode full step operation.
• Alternate one phase on mode, Two phase on
mode, half step operation.
• Micro stepping

13. One phase on mode full step operation
A B ANGLE
IN
DEGRE
ES
A+ + 0 0
B+ 0 + 90
A- - 0 180
B- 0 - 270
A+ + 0 0

14. Two phase on mode full step operation
A B ANGLE(DEG)
A+B+ + + 45
B+A- - + 135
A-B- - - 225
B-A+ + - 315
A+B+ + + 45

15. Alternate one phase on mode,Two
phase on mode, half step operation
A B ANGLE(DEG)
A+ + 0 0
A+B+ + + 45
B+ 0 + 90
B+A- - + 135
A- - 0 180
A-B- - - 225
B- 0 - 270
B-A+ + - 315
A+ + 0 0

16. HYBRID SYNCHRONOUS STEPPER
motor
• Combination of pm and vr techniques
• achieve maximum power in a small package
size.

18. Phase current waveforms
•WAVE DRIVE
•FULL STEP DRIVE
•HALF STEPPING
•MICRO STEPPING

19. Wave drive
• only a single phase is activated at a time.
• same number of steps as the full step drive,
• motor will have significantly less than rated torque.
• It is rarely used.

20. Full step drive
• usual method for full step driving the motor
• Two phases are always on.
• The motor will have full rated
• Wave drive and single phase full step both are one
and the same.

21. Half stepping
• drive alternates between two phases on and a single
phase on.
• increased angular resolution, motor has less torque
(approx. 70%) at the half step position (where only a
single phase is on).
• This may be mitigated by increasing the current in
the active winding to compensate.
• advantage -drive electronics need not change to
support it.

22. Micro stepping
• Sine cosine micro stepping most common but other waveforms
can be used.
• Regardless of the waveform used
• as the microsteps become smaller, motor operation becomes
more smooth,
• reduced resonance in any parts of connection /motor itself.

23. APPLICATIONS
• They are commonly used in watches and old electric meters
• They are used in wide variety
1. In Industry
As - Drilling Machine,
- Grinder,
- Laser Cutting,
- Conveyor;&
- Assembly Lines.
2. In computer Peripherals
As - Printer,
- Plotter,
- Tape Reader,
- Card Reader;&
- Copy Machines.
3. In Business
As - Banking systems;&
- Automatic typewriters.
4. In Motion Control and Robotics
As - Silicon Processing;&
- I.C. Bonding.

24. BIBLIOGRAPHY
• Book: Basic Electrical Engineering
Author: DC Kulshreshtha
• http://en.wikipedia.org/wiki/Stepper_m
otor
• http://www.omega.com/auto/pdf/REF_I
ntroStepMotors.pdf
• http://users.ece.utexas.edu/~valvano/D
atasheets/StepperMicrostep.pdf
• http://zone.ni.com/devzone/cda/ph/p/i
d/287#toc2