The Series System of Street Lighting Distribution

The series system of distribution has been used almost universally for street lighting since the first use of electric lamps. Lamps, both arc and incandescent are very simple and more efficient when designed for series operation than are the multiple type. The maintenance of constant power at the lamp terminals where lamps are thinly scattered over a wide area is much easier with a series system of distribution than with any other system. The burning of all street lamps in the city for certain specified hours makes it desirable to turn the whole circuit on and off from a certain point so that such a system whether series or multiple cannot be used to distribute power for other purposes. As therefore, a special system is necessary for the street lamps, it has usually been made of the series type for the above reasons. The special apparatus required to operate a series system from constant potential is very simple and inexpensive. The constant-current moving-coil transformer is the main factor in the maintenance of the necessary constant current. The film cut-out socket for the lamp enables the continuity of the circuit to be maintained when the incandescent lamp breaks or is removed. Both are very simple and reliable even with unskilled operators.