WESTINGHOUSE MAGNETIC BRAKE FOR ELECTRIC TRAMCARS.

Progress, Volume I, Issue 2, 1 December 1905, Page 31

WESTINGHOUSE MAGNETIC BRAKE FOR ELECTRIC TRAMCARS.

The Westinghouse magnetic brake is the outcome of the unequalled experience of the Westinghouse Company, in the manufacture of brakes of all kinds. It has been designed to suit all conditions of tramway traffic, more especially those which exist in city streets, where it is absolutely essential that cars should be controlled by a brake of the most powerful and reliable description. It is instantaneous in action, and its power can be easily regulated by the driver for ordinary stopping or slowing down, as well as for the shortest stops required in case of emergency. The Westinghouse magnetic brake is, therefore, a combined service and emergency brake. Being simultaneously a track, wheel, and axle brake, it is capable of exercising the maximum braking power which it is desirable to apply to a moving car. Even whenin cases of extreme emergency-it becomes necessary to put the brake full on suddenly while the car is travelling at high speed, the consequent rapid retardation is smooth, and there is an entire absence of the jerking which characterises the action of emergency brakes of other types. The short stops effected by it, while causing no discomfort to passengers, allow the drivers to run their cars safely through congested traffic at higher speeds, and with minimum headway. On tramway systems where the cars are equipped with the Westinghouse magnetic brake, higher speeds than ordinary have been sanctioned. The effect of higher schedule speeds is that a given service can be maintained with fewer cars, with resulting greater economy in operating expenses, and this means that with a given number of cars the service can be improved, The action of the Westinghouse magnetic brake is quite independent of the current on the line, and even if the latter be cut off while a car is quickly running down a steep incline, the brake may be applied with equal facility and effectiveness ; and

one of the characteristics of the brake is that it is as positive in its action at 2 miles per hour, as at 20 miles per hour. Furthermore, its application requires no skill on the part of the motorman. The Westinghouse magnetic brake consists of :- A track magnet with detachable soft steel trackshoes fixed to each pole. The shoes run just clear of the rails, and the magnet is energised by current from the car motors acting as generators— brake-blocks, or wheel-shoes of the ordinary type, acting on the wheels. There is a simple link mechanism connecting the 'track-shoes and wheelshoes. By means of this the downward pull, and consequent drag on the rails of the magnetised track-shoes, is transmitted to the wheel-shoes, which act upon the peripheries of the wheels in. the usual way. The constructional details of the brake may bebetter understood by reference to illustration. The track magnet is a horse-shoe with the polepieces parallel with the rails, the poles taking the form of renewable track-shoes. The magnet core is horizontal, and the coil is enclosed in a strong water-tight brass sheath. The whole isflexibly suspended by helical steel springsfrom the truck frame, thus allowing the trackshoes to ride over obstructions. The ordinary clearance between the shoes and the rail is |inch. The electrical connections of the magnet consist of strongly armoured cables in duplicate. The entire mechanism is of the simplest character, and does not in any way interfere with the operation of the hand brake. A single truck equipment includes the above three elements in duplicate, a bogie or double truck car being fitted with the equivalent of twosingle truck equipments. This brake has been, successfully fitted to every type of truck in use. The Wellington and Dunedin tram cars are the only ones fitted with the Westinghouse magnetic brake, in addition to the ordinary ratchet. Auckland cars have a powerful, but slow-acting shoe-brake, operated on by a ratchet, in addition to the ordinary ratchet brake ; while Christchurch cars are equipped with a compressed air brake, also in addition to the ratchet. The standby for all electric systems, but which is seldom used, is the reversing of motors, by which the operation of the controller causes the motors to generate in opposition to one another, and so retard the progress of _ the car. fr 1