2. TYPES
• VARIABLE RELUCTANCE STEPPER MOTOR
a)Single stack
b)Multi-stack
• PERMANENT MAGNET STEPPER MOTOR
• HYBRID STEPPER MOTOR
3. i) Single phase ON method (step angle=90)
1. a)SINGLE STACK VARIABLE RELUCTANCE STEPPER MOTOR
4. ii)Two phase ON method (step angle =90)
Advantage: HIGH torque compared to single phase ON method
5. Disadvantage :
1) High torque ripple (uneven torque due to high current excitation at position 2,4,6,8.
2 ) So we need to regulate the current using PWM (pulse width modulation technique)
iii)Single phase and two phase ON method (Step angle=45)
7. 1) ANTICLOCKWISE DIRECTION OF
ROTATION=??
In all modes of excitation we can get the anticlockwise
direction by changing the excitation in the poles
2) DRIVE CIRCUITS??
UNIPOLAR DRIVE CIRCUITS (Because we don’t need to change the direction of
Current (or) we don’t need to care about the poles (North or south) in the
Stator windings.
10. • Energizing phase (stack) A: when stack A winding is energized, the
rotor teeth will move to align themselves with the stator teeth is stack A
as shown in Figure
• Energizing phase (stack) B: when stack B winding is then energized
while stack A winding is de-energized, the rotor teeth will move to align
themselves with the stator teeth is stack B. This will result in a clockwise
rotation of the rotor by 10° as shown in Figure
• Energizing phase (stack) C: when stack C winding is then energized
while stack B winding is de-energized, the rotor teeth will move to align
themselves with the stator teeth is stack C. This will result in another
clockwise rotation of the rotor by 10°. After this stage the rotor has
moved one rotor tooth pitch as illustrated
11.
12. 2.PERMANENT MAGNET STEPPER MOTOR
Fig - Construction and operation of two phase Permanent magnet stepper motor
(Step angle =90)
13. 1) ANTICLOCKWISE ROTATION ?
2) STEP ANGLE =45 by alternate single
and two phase on ? Tabular column ?
3) DRIVE CIRCUITS??
Bipolar Drive circuits
