91
J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
LF
®
The LF actuators are provided with an adjustable stop to limit
the rotation of the actuator. This function works in conjunction
with the universal clamp or the optional position indicator.
The adjustable stop is needed when rotation of less than 95°
is required. The LF actuator can be indefinitely stalled, in any
position, without harming the actuator.
Using the universal clamp:
1. Loosen the end stop fastening screw using a #2 Phillips
screwdriver.
2. Move the stop block so the bottom edge of the block lines
up with the number corresponding to the desired degrees
of rotation. (example: 45 degrees of rotation = .5)
3. Lock the block in place with the fastening screw.
4. Check the actuator for proper rotation.
Using the IND-LF position indicator with adjustable stop:
Note: preferred method if short shaft mounting is used.
1. With the actuator in its fail-safe position, place the IND-LF
Position Indicator so that it points to the 0 degree position.
2. Loosen the end stop fastening screw using a #2 Phillips
screwdriver.
3. Move the stop block so the bottom edge of the block lines
up with the number corresponding to the desired degrees
of rotation. (example: 45 degrees of rotation = .5)
4. Lock the block in place with the fastening screw.
5. Check the actuator for proper rotation.
0
.2
.4
.6
.8
1
Mechanical Angle of Rotation Limiting
Installation Instructions
Quick-Mount Visual Instructions for Mechanical Installation
LF24-SR US actuators have built-in brushless DC motors which provide better accuracy and longer service life.
The LF24-SR US actuators are
d
esigned with a unique non-symmetrical deadband. The actuator follows an increasing or
decreasing control signal with a 80 mV resolution. If 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 slightest deviation very accurately,
yet allowing the actuator to “wait” for a much larger change in control signal due to control signal instability.
Control Accuracy and Stability
Satisfied
Control Position
Satisfied
Control Position
Minimum
Control Resolution
Minimum Reversed
Control Deadband
Prior to Normal Control
80 mV
200 mV
LF Actuator responds to a 80 mV signal when
not changing direction from stop position.
LF Actuator responds to a 200 mV signal when
reversing direction from stop position.
LF24-3 (-S) US and LF24-SR (-S) US actuators have a direction of
rotation switch on the cover labeled “CW-CCW”. Switch position
indicates start point. For the LF24-SR, with the switch in position
“CW”, the actuator rotates clockwise with a decrease in voltage or
current. With the switch in position “CCW”, the actuator rotates
counterclockwise with a decrease in voltage or current.
The LF24-3 (-S) US and LF24-SR (-S) US actuators rotate clock-
wise when the switch is in the “CW” position and power is applied
to wire #3. When power is applied to wire #4 the actuator rotates
counter clockwise.
Rotating the direction of rotation switch to “CCW” reverses the
control logic.
During checkout, the switch position can be temporarily
reversed and the actuator will reverse its direction. This allows
the technician a fast and easy way to check the actuator oper-
ation without having to switch wires or change settings on the
controller.
When the check-out is complete, make sure the
switch is placed back to its original position.
Direction of Rotation Switch
The LF24-MFT(-S) US control accuracy and stability can be found in the MFT specifications, page 293.
