Air port Lighting
Air port Lighting
(OP)
It is said that for air port lighting series lighting circuits are used.Why such a system is used ,instead of normal parallel circuits.Why a constant current regulator ,solid state controland ferro resonant type transformer are required?What are the salient features of ferroresonant type transformer.Who makes such transformers?






RE: Air port Lighting
Series lighting circuits are more economical for long runways, and also make dimming more reliable since all lights see the same current.
Runway lighting design is pretty much cut and paste based on FAA requirements.
RE: Air port Lighting
http://www.flightlight.com/airportlighting/pages/conten...
RE: Air port Lighting
2The disadvantage of parallel circuit is , since the runway lengths are high (9000 ft to 12000ft)in a parallel circuit the light intensity decreases with line drop along the circuit and thereby illumination level is reduced at the far end of the circuit this gives wrong guidance to the pilots who is approaching the runway at very high speed.
3.Some of the advantage of series circuit is given below.
a)A single conductor cable of one conductor size and insulation voltage is used throughout the length.
b)The intensity control of the lamps can be effectively controlled for wide range, to meet different ambience light condition.
c)Since the system is effectively earthed, with one ground fault the system works without effecting the operations.
d)Ground faults can be easily located in series circuit. However, open circuit faults identification is difficult.
4.When compared to parallel light system the series lighting system is expensive due to heavy cost of constant current controller and isolating transformer used for each fitting.
5.The present generations CCRs are manufactured using solid state technology Thyrister type for effective intensity control and circuit protection. Resonant circuits are not presently used in CCRs.
6.One of the majour concern in Series circuit is the very high voltages prodused in open circuit.This aspect is delt efctively by solid state type CCRs.
RE: Air port Lighting
RE: Air port Lighting
1. Series lighting circuit:
a. Drawbacks:
a1. The series circuit provides difficulties in locating any of its opening. The troubleshooting tends to be time consuming and labor cost intensive.
a2. The current regulation is less widespread than voltage regulation.
a3. Any short in individual loads, if not promptly serviced, potentially increases voltage on the remaining loads.
a4. Etc.
b. Advantages:
b1. Single conductor circuit.
b2. Luminaires are equally lit within the circuit.
b3. Current regulation accomplishes equal illumination of luminaires.
b4. Etc.
2. Parallel lighting circuit:
a. Drawbacks:
a1. Two-conductor circuit is required.
a2. Illumination of luminaires is decreasing with circuit length/voltage drop.
a3. Lamps/luminaires with different voltage ratings would be needed to compensate for the voltage drop.
a4. If one lamp or luminaire opens during a plane approach, and one side of runway is less lit, a safety concern is posed.
a5. Etc.
b. Advantages:
b1. One burned lamp is easily detected and replaced with small cost.
b2. Parallel circuit dimming is more widespread.
b3. Voltage drop can be offset by different wire AWG sizes.
b4. Cable deterioration and current to ground leakages can be detected or monitored.
b5. Better safety to an approaching plane for landing since one burned lamp will not pose a major lapse in the runway illumination.
b6. Etc.
RE: Air port Lighting
RE: Air port Lighting
RE: Air port Lighting
RE: Air port Lighting
http://www.elect-spec.com/trnsreg.htm
http://www.power-one.com/technical/articles/topo_e.pdf
for Ferro-resonant transformers
The output V-I characteristics allows the secondary to be short-circuited.
Please notice, that the ferro-resonant transformers do not preclude the lighting circuit in series to be down when a bad connection opens the circuit or the conductor degrades and open the circuit.