Air compressor lay-over control circuit

Claim 1

Control apparatus for controlling compressor operation of a compressed air system of a railway vehicle cooperatively with brake apparatus of the vehicle including a brake pipe normally charged with fluid pressure during a running-vehicle condition, and being void of said fluid pressure during a parked-vehicle condition, said control apparatus comprising: (a) an air compressor; (b) driving means for driving said compressor; (c) a storage reservoir for storing compressed air output from the compressor; (d) power circuit means providing energy for said driving means; (e) primary governor means serially interposed in said power circuit means for maintaining compressor output within upper and lower limits of a high pressure range; (f) secondary governor means serially interposed in said power circuit means in serial relation with said primary governor means for maintaining said compressor output within upper and lower limits of a low pressure range; and (g) monitoring means operably connected to said brake apparatus for sensing the braking condition thereof and including a logic valve device having a control pressure input connected to said brake pipe, said logic valve device being operable responsively to a control pressure signal from the brake pipe during said running-vehicle condition, to a closed position in which communication between said reservoir and said secondary governor means is cut off and said primary governor means is activated exclusively of said secondary governor means, and being operable, in the absence of said control pressure signal during said parked-vehicle condition, to an open position in which said communication is opened for activating said secondary governor means exclusively of said primary governor means.