Belimo TRANE TAF Series, Technical Documentation Manual

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147
I20683 - Subject to change.
Wiring Guide
When an actuator is powered with alternating current (AC), the actual power consumption in watts (W) inside the actuator will remain
the same. However, due to the inductive and capacitive character of the load, a shift between current and voltage occurs (phase
shift). This results in an “apparent” power consumption, which is higher than the actual power consumption. The “apparent” power
consumption is expressed in volt-amperes (VA), which is the product of AC volts and the current (VA = V x I x efficiency.)
The size of a transformer is expressed in volt-amperes (VA) and not in watts (W). The VA rating of a transformer must be
at least as large as the combined VA rating of all the actuators connected to the transformer.
Example: Actuator TAMB24.
Power consumption: 2.5 W. Transformer sizing: 4.5 VA
If five (5) TAMB24 are connected to one transformer, the VA rating of the transformer must be
5 x 4.5 VA = 22.5 VA, or larger.
It is better to use a number of small transformers than one large one.
These products are designed to be powered from Class II transformers for UL applications. These transformers have internal
power limitation. A Class II transformer must not provide more than 30 V and no more than 100 VA output. Do not use a
Class I transformer and fuse, because it does not constitute a Class II power source!
I-L. Wire Sizing
Using the correct wire size is important
when long wire runs are used. Using too
small of a wire increases the resistive
losses of the run. The result of this may
be too low of a voltage at the actuator to
operate correctly. The above chart can
be used to determine the correct wire
size to use for an application.
Example I: Three TAMB24-SR
actuators are powered from the same
wire. The wire run is 100 feet.
Step #1. Calculate the total power
required.
The TAMB24-SR requires 5
VA, 3 actuators are being
used. 3 x 5 = 15 VA Total.
Step #2. Locate 15 VA on the vertical
axis of the chart and 100 feet
on the horizontal axis.
Step #3. Find the intersection of 15VA
and 100 Ft (Point “A”)
Step #4. Read the diagonal line to the
right of point “A”. It is the 18
ga. wire gauge line. Use 18
ga. or larger wire.
Note: A low gauge number = a thicker wire; A high gauge number = a thinner wire.
Example II: The maximum wire length for a 10 VA power consumption using different wire gauges.
Point “B” 22 Ga Max. 60 FT Point “E” 16 Ga Max. 350 FT
Point “C” 20 Ga Max. 120 FT Point “F” 14 Ga Max. 550 FT
Point “D” 18 Ga Max. 220 FT Point “G” 12 Ga Max. 900 FT
Chart 1
100
90
80
70
60
50
45
40
35
30
25
20
15
10
9
8
7
6
5
4
3
2
1.5
1
15 20 25 30 35 40 45 50 60 70 80 90
125 150 200 250 300 350 400 450 500 600 700 800 900
1000 1250 1500 2000
FT WIRE
VA
47 Ft
100 Ft
Example II
A
B
C D
E
F G
12Ga
14Ga
16 Ga
18 Ga
20 Ga
22 Ga
Example I 15 VA
Basic Electricity
1150 1125 1200