[Trade Journal]
Publication: Western Electrician
Chicago, IL, United States
vol. 38, no. 25, p. 515-516, col. 1-3
High-tension Single-phase Traction Experiments on the Seebach-Wettingen Line.
BY DR. ALFRED GRADENWITZ.
In order to have an opportunity of testing the practicability of its current collectors and locomotives, while obtaining some extensive general data for gauging the possibilities of standard gauge electric-railway operation, the Oerlikon Machine Works a short time ago made an agreement with the Swiss Federal Railways, according to which the Seebach-Wettingen standard-gauge line was to be equipped for electric high-tension alternating-current traction, with a view of permanently electrifying that line in the case of satisfactory results of the trial service.
Some data as to the arrangement and results of these interesting experiments follows.
The current used in connection with these experiments is single-phase alternating-current at 15,000 volts, derived from a transformer station. This contains a rotary synchronous motor of 600-horsepower output connected to the distribution system of the machine works (230 volts and 50 periods) and coupled to two generators of 400 kilovolt-amperes each. One of these generators produces alternating current at 750 volts and 50 periods for the operation of the transformer locomotive to be described, while the other supplies alternating current at 750 volts and 15 periods for the operation of another alternating-current locomotive equipped with single-phase commutator motors. The normal speed of rotation of this set is 450 revolutions per minute.
The generators are connected to static transformers, raising the pressure from 750 to 15,000 volts.
The rolling stock comprises in the first place a transformer locomotive (Fig. t). converting the high-tension alternating current of so periods derived from the trolley wire by means of a converter set into direct current serving to feed the motors that drive the axles. The locomotive includes two such motors of 220 horsepower each and four driving axles, and in working condition has a weight of 46 tons.
The effective permanent output at the circumference of the wheels is 400 horsepower, with a speed of 36 to 4o kilometers an hour.
The other locomotive (Fig. 2) is an alternating-current locomotive, equipped with two single-phase commutator motors of zoo horsepower each and provided with four driving axles. The high-tension current of 15 periods derived from the contact wire is reduced by means of two stationary transformers from 15,000 volts to 750 volts. The two motors are connected in series. The weight of the locomotive in working order is 42 tons. while its speed and output are about the same as in locomotive No. 1. The patented rod collectors of the Oerlikon company are used in both locomotives to collect the current.
The experiments have in the beginning been confined to the Seebach-Affoltern section, three kilometers in length, which has been equipped with a side trolley wire eight millimeters in diameter. Three types of suspensions have been tested simultaneously, viz., first, a rigid suspension (Fig. 3); second, an elastic suspension by means of spring slides (Fig. 4), and third, an elastic suspension by means of supporting wires (Fig. 5).
The characteristic features of each of these three suspensions will be seen from the figures.
After having been opened on January 16, 1905, the regular trial service has been carried on up to date without any other interruption than two short intervals in April and June, respectively. Some constructive improvements were made on the locomotive in April last, while the temporary discontinuance in June was made with a view to further the definite installation work in the railway station of Seebach.
All the trial runs were made in the presence and under the supervision of representatives of the Swiss Federal Railways, the first trials being made with the locomotive alone, while trains of a load varying between 150 and 250 tons have been run ever since the middle of March last. No less than 1,746 runs have thus been made, aggregating 5,206 kilometers traversed on the line, and 5,847 kilometers when including the train-forming operations, and runs on the connecting track from the Oerlikon Machine Works to Seebach Station. The number of gross ton-kilometers performed was 631,209.
In the course of. these 1,746 runs only nine disturbances of quite short duration, due to the installation of the plant, were, noticed, while nine other temporary interruptions were to be ascribed to the special conditions of power supply which may be said to be only provisional.
Eight of these temporary disturbances were due to the experimental condition of the plant and were instantly and permanently remedied after some slight alterations in the latter. No disturbance whatsoever has been noted in the current collector equipment ever since August 9, 1905. Only one of the disturbances may be accounted for in the case of normal operation; this is relative to the breakdown of an insulator on the connecting track from the machine works to Seebach Station. No such breakdown has, however, been noted on the experimental track proper. The insulation of the collectors has been found entirely sufficient, even in the case of heavy rains and snowstorms.
It may be said that the electrical installation work both in the stations and on the track, as well as the experiments themselves, gave rise to no disturbance in the normal steam operation of the railway line.
From the results so far given by this experimental operation it is distinctly seen that an electrical-railway service is quite practicable, even at a pressure of 15,000 volts in the trolley wire, while the various current collectors represent a satisfactory solution of the current-collecting problem in the case of standard-gauge railways.
