Patent GB-190424700-A (GB)
Title: Improvements in Systems of Electric Motor Control and in Apparatus therefor
Filed: 1904-11-14
Granted: 1905-09-21
Abstract: 24,700. British Thomson-Houston Co., [General Electric Co.]. Nov. 14. Motors, controlling.- Relates to pneumaticallyoperated train mastercontrol systems which include pneumatic actuating-means and pneumatic maintaining-means. Fig. 1 shows a general arrangement of pneumatic and electric control systems with four trainpipes, the air or other compressed - fluid pipes being shown in thick lines and the conductors in thin lines. RS is the reversing-switch, P the series-parallel switch, and V<1>, V<2> the master valves. Fig. 3 shows a modified arrangement of pneumatic means for a threepipe system. Each contact of the motor controller, Figs. 5, 6, and 7, comprises a cylinder 22 fitted with a piston 23,which in Fig. 1 operates an arm 28 to bridge the contacts 30, a weight serving to restore the switch to the off position. The compressed air is admitted to the cylinder through a quickacting admission and exhaust valve 31, and, when the contact is completely made, a second valve 33 is operated to disconnect the actuating-means and connect the maintaining- means, and at the same time connect the actuating-means with the next contact so as to produce an automatic progression of the contacts. The contact 14 controls the series connection of the motors M', M<2>, the contacts 15, 16 the parallel, and the contacts 17 to 20 the resistances ; the contact 20 controls a short-circuit round the resistances, and prevents the operation of the seriesparallel valve P until the contact has been completely closed. The reversing-switch RS is operated by the pistons 52, 53, the air being admitted through slide valves 33 and spring valves 31 which control the actuating and maintaining systems. On moving a valve V<1> into the first forward position, the pipe 10 of the maintaining- system is first connected to the reservoir B. In the second position, connection is made with the pipe 12 and the actuating-systems, and the reversing-switch is operated ; the air then enters the chamber 34 and operates the slide valve 33, to connect with the maintaining - system and supply air through the pipe 40 to the valve P, and thence through the pipe 41 to the valve 33 of the contact-switch 14, Figs. 5 and 6, and pipe 75 to the valve chamber and cylinder 31 operating the contact. The slide valve 33 is then operated, and changes the pipe connections. The air then flows through the pipe 76 and throttle valve H, which is controlled by a coil to close it should the electric current be excessive, to the resistance switch cylinders 17 to 20. The automatic acceleration may be checked by moving the master valve back to the first position, which opens the actuating- circuit without affecting the maintaining circuit. The valve 33 of the contact 20 is provided with an additional passage way and with pipes 11<b>, 48 serving, when operated, to connect the trainpipe 11 with the valve P, and operate it to make the parallel connections when the master-valve is moved into the parallel position. To prevent the simultaneous operation of the series and parallel contacts 14, 15, 16, their valves have an auxiliary passage way, which opens to exhaust should it be attempted to operate the contacts too soon. Fig. 3 shows the arrangement with three pipes only, the pipe 11 being dispensed with. To obtain series control, air is admitted to one pipe, and, to obtain parallel, to both the pipes 12, 13. In the preferred construction of switch, Fig. 5, the contact-arm 101 is pivoted at 98<a>, and is connected to the piston-rod 24 by a spring 100 at 101<a>, which thus gives it a snap action. A blow-out magnet is provided at 104.