GB130451A - Improvements in and relating to Electro-pneumatic Braking Systems. - Google Patents

Abstract

130,451. British Thomson - Houston Co., (General Electric Co.). July 29, 1918. Fluid-pressure; electric.-Relates to brake systems particularly for electric locomotives, such as described in Specification 117,647 in which the application of the regenerative brake prevents or releases a service application of the air brake. When an .emergency application of the air brake is made, the regenerative brake is cut out instead of the application of both brakes being permitted. The equipment shown is substantially the same as that described in the said prior Specification with the addition of the device for cutting out the regenerative brake. This device comprises a slide-valve 60 normally admitting air from the train-pipe 12 by way of the piston chamber 55 of the locomotive distributing valve DV and pipe 62 to hold open a pneumatic switch 66. When the piston 37 of the distributor DV moves to emergency position it moves the valve 60 to connect the pipe 62 to the exhaust passage 60<1>, thus closing the switch 66, thereby energizing a tripping coil 9 adapted to disengage a latch 45 which holds closed a switch 41 in the circuit of a solenoid 40 controlling a switch in the main power circuit from the trolly T. The latch 45 is that which is also released by tripping coils 7, 8 if the motors A<1>, A<2> are overloaded. The tripping coil 9 is energized by the battery B through the master controller MC. The locomotive distributing valve DV is of the type having a valve 52 which can be actuated by a driver's valve 10 for connecting the brake cylinder BC to the main reservoir MR to obtain an independent application of the locomotive brake or by the actuation of an equalizing valve 58 through, a reduction of train-pipe pressure effected by the valve 11 to apply the locomotive brake with the brakes on the other units of the train which are provided with the usual triple valve TV. The valve RV for preventing or releasing a service application of the locomotive air brake when the regenerative brake is in operation is interposed in the connexion 19, 21 between the distributor DV and brake cylinder BC, and comprises a slide valve 20<a> which normally connects the brake cylinder to exhaust at 22. When, in making an application of the brakes, air is admitted to the pipe 19 it moves the valve 20a to the left, thereby uncovering the pipe 21 and flowing into the brake cylinder. If, however, the regenerative brake is applied, the braking controller BrC connects a battery B to a coil 33 which lowers a double valve 26, 27 from the position shown in which it connects the piston chamber 20 of the valve RV to atmosphere, to one in which this chamber is connected by the pipe 34 to the train-pipe 12, the pressure in which except when an emergency reduction has been effected is sufficient to move the valve 20<a> to the right to connect the brake cylinder to the exhaust port 22. If a service application of the air brakes is attempted when the regenerative brake is applied, the pressure in the chamber 20 of the valve RV prevents movement the valve 20a to the left so that air cannot flow into the brake cylinder BC. The motor system comprises exciter generators G1, G2 which are connected in shunt with the series fields F1, F2 of the motors A1, A2 by the braking controller BrC when these are to act as generators. The generators G1, G2 have series fields s1, s2 and shunt fields f1, f2, the latter being connected to a battery B through a variable resistance r by the braking controller,