1 Actuators relays & motors References • Takashi Kenjo, Akira Sugawara, Stepping motors and their microprocessor controls, Oxford University Press, USA , 1995 • T. R. Kuphaldt, Lessons In Electric Circuits, Volume II – AC, 6th Edition, 2007 (http://www.faqs.org/docs/electric/AC/index.html) • J. Przepiorkowski, Silniki elektryczne w praktyce elektronika, BTC Outline • relays – mechanical – electronic relay (SSR) • stepper motors ( + microsteps) • ac motors
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APH 03 Actuators - 156.17.38.202156.17.38.202/AAE_APDS_lect/APH_03_Actuators.pdf · 22 Permanent magnet motor wavedriving Lessons In Electric Circuits, Volume II –ACBy Tony R. Kuphaldt,
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1
Actuatorsrelays & motors
References
• Takashi Kenjo, Akira Sugawara, Stepping motors and their microprocessor controls, Oxford University Press, USA , 1995
• T. R. Kuphaldt, Lessons In Electric Circuits, Volume II – AC, 6th Edition, 2007(http://www.faqs.org/docs/electric/AC/index.html)
• J. Przepiorkowski, Silniki elektryczne w praktyce elektronika, BTC
Outline
• relays
– mechanical
– electronic relay (SSR)
• stepper motors ( + microsteps)
• ac motors
2
Relays
SPST
SPDT
DPST
DPDT
Single(Double)Pole
Single(Double;Triple)Throw
CO – centre off/change over
example
SPTT=SPCO
Relay
reed relay
3
Relays
AC relay
Relays - types
• Regular
• Latching (bistable)
• Polarized relay
• Reed relay – (mercury wetted)
• Contactor
• Solid state relay– transistor
– triac
– thyristor
• Other (safety switches, over current,……)
4
Relay - diagram symbol
Ohm’s low for inductance
dt
dILU L =
TIPS:
•higher voltage applied – faster changes of current
•fast changes in current – higher voltage induced
•when current change „slope direction” – voltage change
polarity:
•positive voltage applied – current increased
•current decreased – negative voltage induced
LLLL ICi
IXUω1==
Switching on and off an inductor
IL
UCE
UL
UCE
UL
VCC
5
Vcc
+V
GND
R
Relay – spark discharge
UCE
UL
High voltage can destroy
transistor and relay
and can be very dangerous !!!!
Switching on and off an inductor
IL
UCE
ULUCE
UL
VCC+UD
VCC
- UD
protection diode;
flyback diode;
clamp diode;
Vcc
+V
GND
R
Switching on and off an inductor
IL
UCE
UL
UCE
UL
VCC+UD
VCC
- UD- UD-UZ
VCC+UD+UZ
6
Vcc
+V
GND
R
Switching on and off an inductor- series resistor influance
IL
UCE
UL
UCE
UL
VCC+UD
VCC
- UD- UD-UZ
VCC+UD+UZ
Decreasing rise time
(off to on time)
1. Increase Vcc
2. add Rs to preserve Imax
3. result=> higher power
dissipation
Decreasing rise time with current limit
IL
7
Driving relays and motors
I<=1A
Driving relays and motors
BDX…
74HC04
Darlington array ULN2004
http://focus.ti.com/lit/ds/symlink/uln2004a.pdf
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Driving relay/motor
with MOSFET and IGBT
MOSFET
BUZ…
IRF…..
1-30A…
IGBT
..10-300A…
Solid State Relays (SSR)
Solid State Contractor (SSC)
SSR of different typescan be used for AC driven mechanical relays