POWER AND LIGHTS

Evening Post, Volume CXXX, Issue 25, 29 July 1940, Page 9

POWER AND LIGHTS

CORRESPONDENT'S QUERIES

A correspondent, "Veritas," writing in regard to the stoppage of trams in the ctiy last week, asks:

Why the long delays in getting the trams on the way again after a power stoppage, seeing we were told by the Mayor that the power could be switched on again in five to ten minutes from cold starting, when we were asked to vote for the huge cost of the two new turbines erected at Evans Bay power house?

Why are the street lights left on long after daylight, at times till well after 7 a.m.?

The City Council, he suggests, could well economise in the waste of power for street lighting, thereby conserving enough power to carry the heavy load on the trams between 4 and 6 p.m. NOT PRACTICABLE. Inquiries made of officials of the tramway and electricity department brought replies that neither of the remedies proposed by "Veritas" had | practical application.

The stoppage of trams in the City on Wednesday afternoon was not caused by any general interruption of power, but by a fault in the feeder system. Ample power was available, but could not be given the held-up cars until a temporary rearrangement of circuits was made.

Street lighting in Wellington was controlled, not by the clock, but by actual need of lighting, for several years ago the manual control of lighting was replaced by automatic control, though some of the further suburbs were still switched on and off individually.

The master control is at the Jervois Quay sub-station and is a form of the photo-electric cell—an "electric eye" which is motivated by the degree of light above the city and, through various relays, presses buttons and switches to meet need for more light. This master cell and the equipment which goes with it take no notice whatever of clock hours; a fog, a heavy storm cloud, or an umbrella, if someone so disposed knows where it is and climbs up to it, will start the relays of the automatically-controlled street lighting circuits.

The darkest part of the city was in the inner area, the reporter was told, and the control was therefore centrally placed. That might result in the bringing on of lights in the shopping streets while Mount Victoria heights, for instance, still had the last of the day's light, and the reverse with increasing morning light, but generally the automatic control far outdid clock or guesswork control, meeting actual need for lighting, whether in fading evening or brightening morning light, or resulting from fog or storm could.

The suggestion that power saved in the morning might be put on one side for evening use, it was added, was something for which electrical engineers had long striven, but power from the early-morning hours of light demand could not, unfortunately, be piled up in a store to be drawn on later; electric power did not behave that way.