| 摘要 |
700,828. Train lighting systems. STONE & CO. (DEPTFORD), Ltd. Sept. 3, 1952 [Sept. 17, 1951], No. 21796/51. Class 38 (4) The embarkation lights 13' of an "unequipped" railway coach 2 lit on the block system are controlled by an electromagnetic switch having a main winding 15 connected between the usual paralleling main 4 and lighting main 5, an auxiliary winding 19 in series with the embarkation lamps between the lighting main and negative main 6 and arranged to oppose the main winding, and contacts 16, which are closed when the main winding is unexcited, also in series with the lights 13'. By this arrangement, when the axledriven generator of an associated equipped coach 1 is running above a certain speed and the contacts 9, 10 of its cut-in have changed over, the main-winding 15 is energized by the voltage difference between mains 4, 5 (which may be, say, 2 volts) so that contacts 16 are open and lights 13' extinguished. An auxiliary contact 14 on the generator cut-in extinguishes embarkation lights 13 of the equipped coach 1. At speed insufficient to operate the cut-in the mains 4 and 5 are at the same voltage (due to closed contact 10) so that winding 15 is unexcited and the lamps 13' are thus energized. The opposing winding 19 prevents reopening of contacts 16 by a voltage difference between mains 4, 5 as may arise by the surge of current to the lamps when cold. To relieve winding 15 of the full line voltage, which it would otherwise receive whenever the lighting main 5 is de-energized by opening contacts 12 of a master switch, a second electromagnetic switch is provided having a coil 18 energized from the mains 5, 6 and contacts 17, which are open when coil 18 is de-energized, in series with the winding 15. |
