Belimo LF24-SR-E US User manual

•Torque min. 35 in-lb, for control of air dampers
•Built-in adjustable min-position for 3-position and
proportional control
Application
For proportional control with minimum position setpoint, or
three position control of dampers in HVAC systems. Actuator
sizing should be done in accordance with the damper manu-
facturer’s specifications.
The actuator is mounted directly to a damper shaft from 3/8”
up to 1/2”in diameter by means of its universal clamp, 1/2”
shaft centered at delivery. For shafts up to 3/4”use K6-1
accessory. A crank arm and several mounting brackets are
available for applications where the actuator cannot be direct
coupled to the damper shaft.
The actuator operates in response to 24 VAC on wire 2 or 3,
which allows the LF24-SR-E US to retrofit or replace Honeywell®
M8405A actuators.
Operation
The LF series actuators provide true spring return operation for
reliable fail-safe application and positive close-off on air tight
dampers. The spring return system provides constant torque to
the damper with, and without, power applied to the actuator.
The LF series provides 95°of rotation and is provided with a
graduated position indicator showing 0 to 90°.
The LF24-SR-E US uses a brushless DC motor which is con-
trolled by an Application Specific Integrated Circuit (ASIC) and
a microprocessor. The microprocessor provides the intelligence
to the ASIC to provide a constant rotation rate and to know the
actuator’s exact position. The ASIC monitors and controls the
brushless DC motor’s rotation and provides a digital rotation
sensing function to prevent damage to the actuator in
a stall condition. The actuator may be stalled anywhere in its
normal rotation without the need of mechanical end switches.
Power consumption is reduced in holding mode.
See wiring diagrams for LF24-SR-E US for more details on 3-
position control.
Installation
Refer to LF Section of the Standard Actuation and Accessories,
2003 Product Documentation.
Honeywell®is a trademark of Honeywell Inc.
Dimensions (All numbers in brackets are metric.)
LF24-SR-E US
Proportional damper actuator, 24 V for 2 to 10 VDC (or 4 to 20 mA) control signal or 3-position on/off
control, with minimum position potentiometer. Output signal of 2 to 10 VDC for position indication.
Technical Data LF24-SR-E US
Power supply 24 VAC ± 20% 50/60 Hz,
24 VDC ± 10%
Power consumption running: 2.5 W; holding: 1 W
Transformer sizing 5 VA (class 2 power source)
Electrical connection 3 ft, plenum rated cable
1/2”conduit connector
Overload protection electronic throughout 0 to 95°rotation
Control signal Y 0 to 10 VDC, 0 to 20 mA, or 24 VAC
for 3-position on/off control
Input impedance 100 kΩ
Operating range Y 2 to 10 VDC, 4 to 20mA between
0% and 100%
Feedback output U 2 to 10 VDC (max. 0.7 mA) for 95°
Angle of rotation max. 95°, adjust. with mechanical stop
Torque 35 in-lb [4 Nm]
Override function Minimum, Open, Closed via spring
Min-position adjusts on actuator cover
between 0 and 100% (scaled 0 to 1)
Direction of rotation Spring return direction is reversible with
CW/CCW mounting.
Motor direction selected by switch:
CW (Default)=CW with a decreasing signal
CCW=CCW with a decreasing signal.
Position indication visual indicator, 0°to 95°scaled as
0 to 1 (0°is spring return position)
Running time motor: 150 sec constant,
independent of load
spring: < 25 sec
@-4°F to +122°F [-20°C to +50°C]
< 60 sec @-22°F [-30°C]
Humidity 5 to 95% RH non-condensing
Ambient temperature -22°F to +122°F [-30°C to +50°C]
Storage temperature -40°F to +176°F [-40°C to +80°C]
Housing NEMA type 2 / IP54
Housing material zinc coated metal
Agency listings UL 873 listed; CSA C22.2
No. 24 certified, CE
Noise level max: running < 30 db (A)
spring return 62 dB (A)
Servicing maintenance free
Quality standard ISO 9001
Weight 3.2 lbs (1.45 kg.)
LISTED
94D5
TEMP. IND &
REG. EQUIP.
UL

®
0.39" [10]
7.67" [195]
3.66" [93]
1.93"
[49]
6.10" [155]
3.15" [80]
3.86"
[98]
0.256" [6.5] 0.98"
[25]
4.92" [125]
0.79"
[20]
0.5"
[12.7]
0.71" [18]
0.74" [18.7]
2.24"
[57]
3.23" [82]
0.25" [6.3]
Standard:
3/8" to 1/2"
3/8" to 7/16"
Optional
1/2" to 3/4"
w/K6-1
accessory
CCW
D059
56
F20358 / 5 4 3 2 1 -01/04-10M-IG-Subject to change. © Belimo Aircontrols (USA), Inc.

57
F20358 / 5 4 3 2 1 -01/04-10M-IG-Subject to change. © Belimo Aircontrols (USA), Inc.
LF
Three-Position Control Signals
Switch A Wire 2-Red (x)Wire 3-White (D)Position
Open** Any Any Closed
(via spring)
Closed 24 VAC Open Mid-position*
Closed Open 24 VAC Full Open*
Closed 24 VAC 24 VAC Full Open*
* Desired position achieved by driving actuator with motor.
**An example would be to interlock the actuator power supply
with the fan motor starter.
®
LF24-SR-E US
Proportional damper actuator, 24 V for 2 to 10 VDC (or 4 to 20 mA) control signal or 3-position on/off
control, with minimum position potentiometer. Output signal of 2 to 10 VDC for position indication.
Accessories
AV 10-18 Shaft extension (K6-1 is required)
IND-LF Damper position indicator
K6-1 Universal clamp for up to 3/4”diameter shafts
KH-LF Crankarm for up to 1/2”round shaft
Tool-01 10 mm wrench
ZG-LF2 Crankarm adaptor kit for LF
ZG-112 Mounting bracket for replacing Honeywell
Mod IV, M6415 and M8405 type actuators, and
new installations
ZG-LF112 Crankarm adaptor kit for replacing Honeywell
Mod IV, M6415 and M8405 type actuators, and
new installations
ZS-100 Weather shield (metal)
ZS-150 Weather shield (polycarbonate)
Note: When using LF24-SR-E US actuators, only use
accessories listed on this page.
LF24-SR-E US Typical Specification
Spring return control damper actuators shall be direct coupled
type which require no crankarm and linkage and be capable of
direct mounting to a shaft up to a 3/4”diameter and center a
1/2”shaft. Actuator shall deliver a minimum output torque of
35 in-lbs. The actuator must provide proportional damper con-
trol in response to a 2 to 10 VDC or, with the addition of a
500Ωresistor, a 4 to 20mA control input from an electronic
controller. Actuator must have a built-in minimum position
potentiometer. During 3-position control, the actuator shall
drive to minimum position with 24 VAC on wire 2 and drive full
open with 24 VAC on wire 3. Actuators shall use a brushless
DC motor controlled by a microprocessor and be protected
from overload at all angles of rotation. Run time shall be con-
stant, and independent of torque. A 2 to 10 feedback signal
shall be provided for position feedback or master-slave applica-
tions. The actuator must be designed so that they may be
used for either clockwise or counterclockwise failsafe opera-
tion. Actuators shall be UL listed and CSA certified, have a 5
year warranty, and be manufactured under ISO 9001
International Quality Control Standards. Actuators shall be as
manufactured by Belimo.
Wiring diagrams
13
4
5
2
24 VAC Transformer
Blk (1) Common
Red (2) x +Min-position
Wht (3) DYFull Open
Grn (5) UOutput, 2 to 10V
Line
Volts 24 VAC
LF24-SR-E US
.8 .6
.4
.2
0
MIN
1
Default
CW CCW
4
13
24 VAC Transformer
Line
Volts 24 VAC
5
2
Blk (1) Common
Red (2) x +Min-position
Wht (3) DYFull Open
Grn (5) UOutput, 2 to 10V
LF24-SR-E US
.8 .6
.4
.2
0
MIN
1
Default
CW CCW
Notes:
1
2
Provide overload protection and disconnect as required.
Min-position is adjustable from 0 to 100% with
a potentiometer on the actuator cover.
3Actuators with plenum rated cable do not have numbers
on wires; use color codes instead.
4
5
For 3-position control set direction of rotation to CW (Default).
Switch A, actuator spring returns when open (e.g., fan interlock).
W179
W176
3-position control
with a SPDT switch or
two contact closures
(e.g. fan, cooling Y).
Min-position with
Full Open override
(with a single
contact closure).
14
5
52
3
24 VAC Transformer
Blk (1) Common
Red (2) + Hot
Wht (3) Y Input, 2 to 10V
Grn (5) U Output, 2 to 10V
Line
Volts
1
2
Provide overload protection
and disconnect as required.
Actuators may be connected in
parallel. Power consumption and
input impedance must be observed
3
4Actuators with plenum rated cable do not have num-
bers on wires; use color codes instead.
The ZG-R01 500Ωresistor converts the 4-20mA
control signal to 2 to 10 VDC
Actuator may also be powered by 24 VDC.
2 to 10 VDC
Control Signal (–)
(+)
LF24-SR-E US
.8 .6
.4
.2
0
MIN
1
Default
CW CCW
Ω
2 to 10 VDC control of LF24-SR-E US