Modern street-lighting

From Object Wiki

Modern street-lighting
Manufacturer	(unknown)
Production years	(unknown)
Production location	(unknown)

This exhibit shows the way in which a modern time-switch with solar dial controls the switching of street lamps.

[edit] How it works

In the normal instrument the solar dial is rotated by a synchronous motor once every 24 hours, but in the clock exhibited here some gearing has been omitted, so that the dial rotates once per minute. The switching is carried out by means of pins mounted on the three arms of the dial; the position of two of these relative to the dial is automatically varied according to the season of the year, so as to follow the changing times of sunset and sunrise, while the third pin is fixed to operate at selected time adjustable between 11 p.m. and 1 a.m. The switch controls two separate electrical circuits: both are switched ON at sunset, and one is switched OFF at the chosen time between 11 p.m. and 1 a.m.; the other goes OFF at sunrise. Details of the switching action can be seen by watching the switch at work; it will be noticed that both ‘make’ and ‘break’ are rapid. The street lamps in the diorama are controlled by the circuit switching OFF at midnight.

[edit] Memories

Do you remember stories about clocks? Add your memories.

[edit] In the Science Museum's Records

Inv. No: 1953-336