Install Instructions

800-543-9038 USA 866-805-7089 CANADA 203-791-8396 LATIN AMERICA
38
Installation Instruction
s
Electrical Operatio
n
General
The AFB, AFX series actuators utilize both D
C
Motors and brushless D
C
motor
t
echnology. The AFB, AFX uses this motor in conjunction with an Application
S
pecific
Integrated Circuit (ASIC). In the On/Off versions of the AFB and AFX, the ASIC
m
onitors and controls the actuator’s rotation and a digital rotation sensing
f
unction
t
o prevent dama
g
e to the actuator. The AFB24, AFX24… modulates type actuators
incorporate a built in microprocessor. The microprocessor provides the intelligence
t
o the ASIC to provide a constant rotation rate and knows the actuator’s exact zero
p
osition.
Brushless DC Motor Operation
Belimo’s brushless D
C
motor spins by reversing the poles of stationary
electromagnets housed inside of a rotating permanent magnet. The electromagnetic
p
oles are switched by a special A
S
I
C
circuit developed by Belimo. Unlike the
c
onventional DC motor, there are no brushes to wear or commutators to foul.
Overload Protection
The AFB, AFX series actuators are protected
f
rom overload at all an
g
les o
f
rotation.
The ASIC circuit constantl
y
monitors the rotation of the DC motor inside the actuator
and stops the pulses to the motor when it senses a stall condition. The DC motor
r
emains energized and produces full rated torque to the load. This helps ensure that
dampers are fully closed and that ed
g
e and blade seals are always properly
c
om
p
ressed.
Motor Position Detection
Belimo brushless DC motors eliminate the need for potentiometers for positioning in
m
odulatin
g
type actuators. Inside the motor are three “Hall Effect” sensors. These
s
ensors detect the spinnin
g
rotor and send pulses to the microprocessor which
c
ounts the pulses and calculates the position to within 1
/
3 of a revolution of the
m
o
t
or.
Control Accuracy and Stability
AFB
24-
MFT
,
AFX
24-
MFT
actuators
have built-in brushless DC motors
which
p
rovide better accurac
y
and
longer service life.
T
he A
F
B
2
4-MFT, AFX24-MFT actuators are designed with a unique non-sym-
metrical deadband. The actuator follows an increasin
g
or decreasin
g
control
s
ignal with a 80 mV resolution. I
f
the signal changes in the opposite direction,
the actuator will not respond until the control signal changes by 200 mV. This
allows these actuators to track even the sli
g
htest deviation very accurately, yet
allowing the actuator to “wait” for a much larger change in control signal due
to control signal instability.
8
8
Note: Resolution is a percenta
g
e o
f
operatin
g
ran
g
e. 1% in one direction,
2.5% when chan
g
in
g
direction. 2-10 VD
C
control example shown above
.
M40024 - 05/10 - Subject to change. © Belimo Aircontrols (USA), Inc.