Airfield Lighting
Safegate Group
Manual
Date: October 2016
Ref: SL-RE-E_SL-RT-E_SL-RN-E_SL-RTN-E_SL-SB-E
Version: 1.4
Page 8 of 42
1.2.2
Selection of Isolation Transformer
1.2.2.1
2.8-6.6A System
An isolation transformer in a series system has a specified current ratio (normally
6.6/6.6A) that is considered to be fixed as long as the load does not exceed the
nominal wattage of the transformer.
Most manufactures specify a certain spare capacity (20-30%).
When the load exceeds the nominal wattage, the transformer begins to saturate, the
current ratio drops as a function of the overload. To avoid this current drop (intensity
drop) the nominal wattage should not be exceeded. It is even more important in a
system with SafeLED IQ where the IQ function adds a secondary load for its power
consumption.
Note: The SafeLED (without IQ) is not to be connected to transformers larger than
100W.
The secondary load of an isolation transformer in a SafeLED IQ system includes:
Light fixture load
Cable losses
1.2.2.2
Light Fixture Load
The light fixture load is the total wattage of the light fixture.
Description
Total wattage
Runway Edge Elevated White-White for
Precision Approach L-862(L)
27 W
Runway Edge Elevated Yellow-White for
Precision Approach L-862(L)
26 W
Runway Edge Elevated Red-White for
Precision Approach L-862(L)
23 W
Runway Edge Elevated Red-Yellow for
Precision Approach L-862(L)
21 W
Runway Edge Elevated White-White for
Circular Guidance L-862(L)
36 W
Runway Edge Elevated Yellow-White for
Circular Guidance L-862(L)
34 W
Runway Edge Elevated Red-White for
Circular Guidance L-862(L)
30 W
Runway Edge Elevated Red-Yellow for
Circular Guidance L-862(L)
28 W
Runway Threshold Elevated
20 W
Runway Threshold Elevated L-862E(L)
10 W
Runway End Elevated
15 W
Runway End Elevated unidirectional
L-862E(L)
15 W
Runway End Elevated bidirectional
L-862E(L)
23 W
Runway Threshold/End Elevated
28 W
Runway Threshold/End Elevated L-862E(L)
18 W
Stop Bar Elevated
10 W
Stop Bar Elevated L-862S(L)
15 W
