Insel rectifiers manufacture isolating transformers, which are used in airfield lighting system. These transformers provide isolation between the primary high voltage series circuit and low voltage secondary circuit. Isolating transformers are used in airfield lighting system. These transformers provide isolation between the primary high voltage series circuit and low voltage secondary circuit. The primary of all transformers are connected in series and fed by constant current regulator, secondary feeds the individual airport runway light. Isolating transformers are used to maintain continuity of high voltage primary circuit when one or more lamps are not in working order and to maintain the supply of 20 amp from the 6.6 amp series circuit or vice-versa alternatively to supply 6.6 amps.
