Install Instructions

800-543-9038 USA 866-805-7089 CANADA 203-791-8396 LATIN AMERICA
91
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.
Alwa
y
s read the controller manufacturer's installation literature carefull
y
b
efore making any connections. Follow all instructions in this literature. If you
have an
y
q
uestions, contact the controller manufacturer and/or Belimo.
Transformers
The NFB24, NFX24…actuators require a 24 VA
C
class 2 transformer and draws a
maximum of 10 VA per actuator. The actuator enclosure cannot be opened in the
f
ield, there are no parts or components to be replaced or repaired.
– EMC directive: 89/336/EEC
–
S
oftware 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.
Multiple Actuators, One Transformer
Multiple actuators may be powered from one transformer provided the followin
g
rules
a
r
e
f
o
ll
o
w
ed:
1. The TOTAL current draw of the actuators
(
VA ratin
g)
is less than or equal to the
ratin
g
o
f
the trans
f
ormer.
2. Polarit
y
on the secondar
y
o
f
the trans
f
ormer is strictl
y
f
ollowed.
Thi
s means t
h
a
t
a
ll No. 1 wires
f
rom all actuators are connected to the common le
g
on th
e
t
rans
f
ormer and all No. 2 wires
f
rom all actuators are connected to the hotle
g
.
Mixing 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 si
g
nal may be powered from
multiple trans
f
ormers provided the
f
ollowin
g
rules are
f
ollowed
:
1. The trans
f
ormers are
p
ro
p
erl
y
sized
.
2. All No. 1 wires
f
rom all actuators are tied to
g
ether and tied to the ne
g
ative le
g
o
f
the control signal.
S
ee wiring diagram
.
Wire Length for NFB..., NFX... Actuators
K
eep power w
i
re runs
b
e
l
ow t
h
e
l
en
g
t
h
s
li
ste
d
i
n t
h
e F
ig
ure H. I
f
m
o
r
e
th
a
n
o
n
e
a
ctuator is powered
f
rom the same wire run, divide the allowable wire length by the
n
umber o
f
actuators to determine the maximum run to any single actuator.
Example: 3 actuators, 16 Ga wire
350 Ft ÷ 3 Actuators = 117 Ft. Maximum wire ru
n
M
AXIMUM WIRE LENGTH FOR 10V
A
W
ire
S
ize
M
ax.
F
eet. Wire
S
ize
M
ax.
F
ee
t
12 Ga 900 Ft.
1
8 Ga 220 Ft
.
14 Ga 550 Ft. 20 Ga 120 Ft.
1
6
Ga
350
Ft. 22
Ga
60
Ft
.
FIGURE
H
Wire Type and Wire Installation Tips
For most installations
,
18 or 16 Ga. cable works well with the NFB24
,
NFX24...
a
ctuators. Use code-approved wire nuts, terminal strips or solderless connectors
where wires are joined. It is good practice to run control wires unspliced
f
rom the
a
ctuator to the controller. I
f
splices are unavoidable, make sure the splice can be
r
eached for
p
ossible maintenance. Ta
p
e and/or wire-tie the s
p
lice to reduce the
p
ossibility of the splice bein
g
inadvertently pulled apart
.
Th
e
NFB
24,
NFX
24... proport
i
ona
l
actuators
h
ave a
di
g
i
ta
l
c
i
rcu
i
t t
h
at
i
s
d
es
i
gne
d
to
ignore most unwanted input signals (pickup). In some situations the pickup may be
severe enou
g
h to cause erratic runnin
g
of the actuator. For example, a lar
g
e
inductive load
(
hi
g
h volta
g
e AC wires, motors, etc.
)
runnin
g
near the power or
control wirin
g
may cause excessive pickup. To solve this problem, make one or
more o
f
the
f
ollowing changes:
1. Run the wire in metallic conduit
.
2
. Re-route the wirin
g
away
f
rom the source o
f
pickup
.
3. Use shielded wire
(
Belden 8760 or equal
)
. Ground the shield to an earth ground.
Do not connect it to the actuator common.
Initialization of the NFB24-MFT, NFX24-MFT
When power is initially applied, the actuator will
f
irst release its manual preload
p
osition (This assumes a manual position has been set). The actuator will then rotate
to the full fail-safe position. At this point the microprocessor recognizes that the
a
ctuator is at full fail-safe and uses this
p
osition as the base for all of its
p
osition
calculations. The microprocessor will retain the initialized zero durin
g
short power
f
ailures o
f
up to 20 seconds. The NFB24-MFT and NFX24-MFT will also return to its
p
osition prior to the 20-second-or-less power loss. For power failures
g
reater than
2
0 seconds, the actuator would naturall
y
return to its full fail-safe
p
osition
p
rior to the
microprocessor losin
g
its memory. The actuator will also re-initialize i
f
the manual
p
os
i
t
i
on mec
h
an
i
sm
i
s use
d
.
I
n
s
t
alla
t
io
n
I
n
s
tr
uc
t
io
n
s
General Wirin
g
Instruction
s
M40024 - 05/10 - Subject to change. © Belimo Aircontrols (USA), Inc.