The development of electricity as a motive power is engaging the attention of scientific men in a variety of ways ; and yesterday, upon a mile length of tramway at Northfleet, the Series Electrical Traction Syndicate, by practical demonstration, showed how they can run cars by fixed conductors charged from a stationary engine and dynamo at the generating station and distributing electricity to the cars in series. This is a new principle, and the success at the trials yesterday was unmistakable. The mechanical difficulties which have hitherto induced engineers to confine their attention to either the parallel or the multiple arc method of distribution have been overcome. The syndicate claim that by the introduction of the Series principle cheap electrical traction on a large scale is now for the first time made possible at less than one-sixth of the initial expenditure, and consequently at less than one-sixth the cost of older methods. Although in this country comparatively little has been done towards the employment of electricity in the locomotive work of the highways, in the United States there are upwards of fifty electrical roads in actual operation, and about seventy more in course of construction. The cars are to all intents and purposes the same in appearance as those with which the public are familiar. Underneath one of the rails of the track is laid a conduit eight inches in width, and thirteen inches below the surface of the road. It is, however, open at the surface to a width of fiveeighths of an inch. The rail on the other side has a small slot of seven-eighths of an inch in width. From the conduit the electric current is passed to the cars by what are termed spring jacks, occurring at intervals of twenty • one feet, each spring jack containing contact points constructed of gun metal checks pressed closely together by spiral springs ; and the points, mounted on glazed earthenware, are electrically connected by an insular cable. The speed can be perfectly regulated, and the cars can, in fact, be made to travel much more swiftly than they would be allowed to do by any local authorities. The line at Northfleet has sharp curves, and some sharp pinches of hill, so that the test yesterday was of the severest character. The cost of working it is said to be less than half that of horse power. It may be added that the spring jacks are arranged so that they can be taken out or replaced in the conduit in the course of a few minutes. Necessary as they are, they are simple and inexpensive pieces of apparatus. The motors are mounted underneath the car, and are run at 400 revolutions per minute, delivering at this speed a maximum of fifteen horse-power on the brake. The regulation of the motors is attained by massively constructed switches mounted on each platform . Some of the subsidiary advantages ef the Series system are that by using highly insulated cables, and exposing but small surfaces of conductor, a perfect insulation is obtained; renewals can be effected without interfering with the traffic; the conduit can be easily cleaned, and faults in the line are easily detected by the car-drivers themselves ; and there is ample protection of the spring jacks from road debris. The syndicate believe that the Series _ system will revolutionise tramway traction in this country, and they base their belief upon the following grounds“ (1) That the cost of maintenance is not subject—as is the case with horses—to variations in the price of provender, etc.; (2) That tramway companies are eagerly watching for a system capable of taking the place of animal power, even at the same cost; (3) That steam and compressed air have been tried with very qualified success, the former being especially objectionable on the score of expense, noise, dirt, smoke, steam, and smell; (4) That tramways can bo operated by the Series system at less than one-half the cost of horses; and (5) That the Series system is, moreover, cheaper than every other form of mechanical traction.” ‘ Daily News.’
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Electrical Development., Evening Star, Issue 7906, 14 May 1889
Electrical Development. Evening Star, Issue 7906, 14 May 1889
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