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Jeff Shelton – 10 March 2015 1
Jeff Shelton – 10 March 2015
Shaft (Rotor) Angle
I1
I2
I3
2
Jeff Shelton – 10 March 2015
Electric Motors
DC Motors
Permanent Magnet
Series Wound
Compounded
Shunt Wound
Separately Excited
Brushed
Brushless
Stepper
AC Motors
Reluctance
Hysteresis
Synchronous
Induction
Wound Rotor
Squirrel Cage
Permanent Magnet
3
Jeff Shelton – 10 March 2015 4
Image: http://electronics.howstuffworks.com/brushless-motor.htm
Jeff Shelton – 10 March 2015 5
Image: http://www.rcuniverse.com/magazine/reviews/1344/BrushlessMotors7.jpg
Jeff Shelton – 10 March 2015
Shaft (Rotor) Angle
I1
I2
I3
6
Jeff Shelton – 10 March 2015
7
Jeff Shelton – 10 March 2015
Electric Motors
DC Motors AC Motors
Permanent Magnet
Brushed
Brushless
Reluctance
Hysteresis
Stepper
Synchronous
Induction
Wound Rotor
Squirrel Cage
Series Wound
Compounded
Shunt Wound
Separately Excited
Permanent Magnet
8
Jeff Shelton – 10 March 2015 9
What does it all mean?
Image: http://www.pololu.com/category/87/stepper-motors
Jeff Shelton – 10 March 2015
10
Image: http://www.engineersgarage.com/articles/stepper-motors
Jeff Shelton – 10 March 2015 11
Motor Driver
Current to Windings
Indexer Step Pulses
Controller
Movement Sequence
Images: http://www.automationdirect.com/adc/Overview/Catalog/Motion_Control/Stepper_Systems
Jeff Shelton – 10 March 2015
12
Jeff Shelton – 10 March 2015
13
Jeff Shelton – 10 March 2015
N N
N
A
A'
B B'
14
Jeff Shelton – 10 March 2015
15
N N
N
A
A'
B B'
Jeff Shelton – 10 March 2015 16
N N
N
A
A'
B B'
Jeff Shelton – 10 March 2015
N
N
N N
N
Initial equilibrium state
Horizontal winding field reversed (no motion yet)
Motion starts toward new equilibrium
Reach new equilibrium
N N
S
S N
N
N
N S
N N
S
N N
N
S
N
S
N
N
N S
S
N
N
N
17
Jeff Shelton – 10 March 2015 18
S N S N N S
Jeff Shelton – 10 March 2015
ℱ
19
+ –
ℱ = 𝑁𝑖
Jeff Shelton – 10 March 2015 20
+ –
ℱ = Φ ℜ𝑚
𝑉 = 𝑖 𝑅
Jeff Shelton – 10 March 2015 21
+ –
Core
ℱ = Φ ℜ𝑚
Jeff Shelton – 10 March 2015
Φ
ℜ𝑚
22
Φ =𝑁𝐼
ℜ𝑚
+ –
Core
Jeff Shelton – 10 March 2015 23
Φ =𝑁𝐼
ℜ𝑚
+ –
Core
Jeff Shelton – 10 March 2015 24
Jeff Shelton – 10 March 2015 25
Jeff Shelton – 10 March 2015 26
N S
Jeff Shelton – 10 March 2015
β
27
𝛽 =𝑁𝑠 − 𝑁𝑟
𝑁𝑠 ∙ 𝑁𝑟× 360°
30°
Jeff Shelton – 10 March 2015
1 1
2
2
3
3
1 1
2
2
3
3
1 1
2 3
1 1
2 3
2 3 2 3
28
Jeff Shelton – 10 March 2015
29
Jeff Shelton – 10 March 2015
S
S S N
N N
N
S
S
S
S
N
N
N
S S
S
N
N N
30
N S
N
S
N S
Jeff Shelton – 10 March 2015 31
Comparison adopted from: http://www.automotsys.com.au/stepserv.html
Jeff Shelton – 10 March 2015 32
Comparison adopted from: http://www.automotsys.com.au/stepserv.html
Jeff Shelton – 10 March 2015 33
Comparison adopted from: http://www.automotsys.com.au/stepserv.html
Jeff Shelton – 10 March 2015
A
B
(a) (b) (c) (d)
A
B ON
OFF ON
OFF ON
OFF ON
OFF
34
Jeff Shelton – 10 March 2015
A
B
(a) (b) (c) (d)
A
B
35
Jeff Shelton – 10 March 2015 36
Jeff Shelton – 10 March 2015 37
Vs
GND
Jeff Shelton – 10 March 2015 38
Vs
GND
Have to swap leads to reverse magnetic polarity
Jeff Shelton – 10 March 2015 39
Vs
GND
Have to swap leads to reverse magnetic polarity
Vs
GND
Vs or GND
Jeff Shelton – 10 March 2015 40
Vs
GND
Have to swap leads to reverse magnetic polarity
Vs
GND
Vs or GND
No lead swapping, but less torque production
Jeff Shelton – 10 March 2015
⟹
41
On the same frame, bipolar motors can deliver about 40% more torque than
unipolar motors
Jeff Shelton – 10 March 2015 42
1 2 3 4
Phase 1
Phase 2
Jeff Shelton – 10 March 2015
1 2 3 4
Phase 1A (Q1)
Phase 1B (Q2)
Phase 2C (Q3)
Phase 2D (Q4)
43
Jeff Shelton – 10 March 2015
Q5 Q6
Q7 Q8
A
B
(1) (2) (3) (4)
A B
A
B
(1) (2) (3) (4) (5) (6) (7) (8)
44
Jeff Shelton – 10 March 2015
Pulse
Direction
Q1 Q2 Q3 Q4
Input: P & D
Output: Q1 & Q3
2 1 and 4 3Q Q Q Q
S0
S3 S2
S1
11 10
00 01
11
11
11
11
10
10
10
10
1 2 3 4
Phase 1A (Q1)
Phase 1B (Q2)
Phase 2C (Q3)
Phase 2D (Q4)
45
Jeff Shelton – 10 March 2015
46
Jeff Shelton – 10 March 2015
47
Jeff Shelton – 10 March 2015 48
Jeff Shelton – 10 March 2015 49
Jeff Shelton – 10 March 2015
Time
Step
(A
ngu
lar
Posi
tio
n)
50
Jeff Shelton – 10 March 2015
51
Jeff Shelton – 10 March 2015
52
Jeff Shelton – 10 March 2015
Torque
Spee
d (
Step
Rat
e)
Start/Stop Curve (limit)
Slew Curve (limit)
53
Jeff Shelton – 10 March 2015
54
Jeff Shelton – 10 March 2015 55
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