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16
Multi-Function Technology
®
Wiring
WARNING The wiring technician must be trained and experienced
with electronic circuits. Disconnect power supply before attempting
any wiring connections or changes. Make all connections in
accordance with wiring diagrams and follow all applicable local and national
codes. Provide disconnect and overload protection as required. Use copper,
twisted pair, conductors only. If using electrical conduit, the attachment to the
actuator must be made with flexible conduit.
Always read the controller manufacturer's installation literature carefully
before making any connections. Follow all instructions in this literature. If you
have any questions, contact the controller manufacturer and/or Belimo.
Transformer(s)
Non-spring return actuators require a 24 VAC class 2 transformer and draws a
maximum of 5 VA per actuator. The actuator enclosure cannot be opened in the
field, there are no parts or components to be replaced or repaired.
– EMC directive: 89/336/EEC
– Software class A: Mode of operation type 1
– Low voltage directive: 73/23/EEC
CAUTION: It is good practice to power electronic or digital controllers from a
separate power transformer than that used for actuators or other end devices.
The power supply design in our actuators and other end devices use half wave
rectification. Some controllers use full wave rectification. When these two
different types of power supplies are connected to the same power transformer
and the DC commons are connected together, a short circuit is created across
one of the diodes in the full wave power supply, damaging the controller. Only
use a single power transformer to power the controller and actuator if you know
the controller power supply uses half wave rectification.
Typical Transformer Sizing
Actuator Series Voltage Required VA Per Actuator
New Generation AF 24 10*
Original AF 24 10
New Generation NF 24 9**
Original NF 24 6
LF 24 6
TF 24 4
GMB/GRB 24 7
AMB/ARB 24 6
NMB 24 6
LMB/LRB 24 5
AHB 24 6
LHB 24 5
LUB 24 5
AMQB 24 18
NMQB 24 18
LMQB 24 18
AHQB 24 18
LHQB 24 18
* @ 70 second run time
** @ 40 second run time
Multiple Actuators, One Transformer
Multiple actuators may be powered from one transformer provided the following
rules are followed:
1. The TOTAL current draw of the actuators (VA rating) is less than or equal to
the rating of the transformer.
2. Polarity on the secondary of the transformer is strictly followed. This means
that all No. 1 wires from all actuators are connected to the common leg on
the transformer and all No. 2 wires from all actuators are connected to the
hotleg. Switching wire No. 1 & 2 on one leg of the transformer will result in
erratic operation or failure of the actuator and/or controls.
Multiple Actuators, Multiple Transformers
Multiple actuators positioned by the same control signal may be powered from
multiple transformers provided the following rules are followed:
1. The transformers are properly sized.
2. All No. 1 wires from all actuators are tied together and tied to the negative leg
of the control signal. See wiring diagram on page 11.
Wire Lengths for Actuators
Keep power wire runs below the lengths listed in the Figure H. If more than one
actuator is powered from the same wire run, divide the allowable wire length by
the number of actuators to determine the maximum run to any single actuator.
Example: 3 actuators, 16 Ga wire
350 Ft ÷ 3 Actuators = 117 Ft. Maximum wire run
LH-24…/LU-24… LM-24.../CM24
Wire Size Max. Feet. Wire Size Max. Feet
16 Ga 1175 Ft. 16 Ga 1125 Ft.
18 Ga 1075 Ft. 18 Ga 750 Ft.
20 Ga 575 Ft. 20 Ga 400 Ft.
22 Ga 300 Ft. 22 Ga 200 Ft.
NM-24…/AH-24…/LMX120… AM-24...
Wire Size Max. Feet. Wire Size Max. Feet
12 Ga 1250 Ft. 12 Ga 1150 Ft.
14 Ga 1130 Ft. 12 Ga 925 Ft.
16 Ga 900 Ft. 16 Ga 550 Ft.
18 Ga 575 Ft. 18 Ga 375 Ft.
20 Ga 300 Ft. 20 Ga 200 Ft.
22 Ga 150 Ft. 22 Ga 100 Ft.
GM…/NMX120…/AMX120…
Wire Size Max. Feet. Wire Size Max. Feet
12 Ga 1125 Ft. 18 Ga 325 Ft.
14 Ga 800 Ft. 20 Ga 175 Ft.
16 Ga 500 Ft. 22 Ga 90 Ft.
FIGURE H – Maximum Wire Lengths
Wire Type and Wire Installation Tips
For most installations, 18 or 16 Ga. cable works well with the non-spring return
actuators. Use code-approved wire nuts, terminal strips or solderless
connectors where wires are joined. It is good practice to run control wires
unspliced from the actuator to the controller. If splices are unavoidable, make
sure the splice can be reached for possible maintenance. Tape and/or wire-tie
the splice to reduce the possibility of the splice being inadvertently pulled apart.
The non-spring return proportional actuators have a digital circuit that is
designed to ignore most unwanted input signals (pickup). In some situations the
pickup may be severe enough to cause erratic running of the actuator. For
example, a large inductive load (high voltage AC wires, motors, etc.) running
near the power or control wiring may cause excessive pickup. To solve this
problem, make one or more of the following changes:
1. Run the wire in metallic conduit.
2. Re-route the wiring away from the source of pickup.
3. Use shielded wire (Belden 8760 or equal). Ground the shield to an earth
ground. Do not connect it to the actuator common.
M40035 - 05/10 - Subject to change. © Belimo Aircontrols (USA), Inc.