THUNDERSTORMS

Sun (Auckland), Volume 1, Issue 33, 2 May 1927, Page 12

THUNDERSTORMS

NEW YORK PREPARED The thunderstorm detector, invented by W. H. Lawrence, chief operator of the Edison Company in 1912, gives warning of the presence of storms as far away as 200 miles. It does this by ringing a bell at intervals of from five to fifteen minutes. As the storm approaches New York City the bell rings more frequently. When it is about two hours away the bell strikes about every half minute. When this occurs the Edison system operator at the central offices orders the reserve boilers into service and the generating units started, the units running at low speed. This done he waits for the bell to start an Insistent warning by ringing continuously. That ordinarily occurs from half an hour to an hour before the storm reaches the city. Often at that time the sky may be still unclouded. But the system operator obeys the bell and sends out a signal simultaneously to the fifty substations and generating stations that tells them to be ready to supply the increased load that will be demanded in a few minutes. i That is why New York is never without lights during the darkness of thunderstorms. Many storms occur in the middle of the day, when there is a demand for a heavy load of electricity for operating the city’s power machines, such as those in factories, elevators, street cars and the like. The increase in the amount of electricity the city needs for its lights during sudden darkness is approximately 75 per cent. Before the detector was invented In 1912 by W. H. Lawrence, chief operating engineer of the Edison Company, a boy used to be stationed on the roof of the building to report the presence of clouds on the horizon. His vision, of course, was limited. And even after be had seen clouds he could only suspect them of harbouring thunderous intentions. WARNINGS ON ANTENNAE While storm clouds are often deceiving in appearance, they have one quality that is characteristic of all of them. They are nearly always accompanied by electrical disturbances in the ether. These disturbances cover a large field. Mr. Lawrence decided that by the use of antennae some of these radiations might be intercepted and, by a suitable apparatus, be made to give warning. The various parts making up the detector are similar to those of the radio and are operated on the same principle. They include an aerial, a short-circuiting switch coherer, condenser, bell, batteries. But these are arranged to record the presence of static rather than to discard it. A study of electric load curves shows that for less than fifty hours during the summer months the city is darkened in the middle of the afternoon by sudden thunderstorms, lasting from half an hour to two hours. During the worst storms the power plants may carry a peak load that exceeds any other peak load of the year. By examining records covering a number of years the Edison Company is able to estimate in advance approximately the number of kilowatts in excess of norma] that will be needed to dispense fhe darkness caused by storms during daylight hours. The engineers have placed the estimate at 200,000 kilowatts for the summer of 1927.