GB206966A - Improvements in track signals for tramways - Google Patents

Abstract

206,966. Payne, J. V. Sept. 13, 1922. Electromagnetic actuation.-In a track signal system for tramways &c. a switch-operating solenoid has two unequal windings f, g, which are energized in series with one another and with lamp or other signals c, d, at the ends of the section when a trolley-contact o is closed by au entering car. Winding f produces a field in opposition to, and overpowering, that due to winding g, so that the core h moves into engagement with a contact k, closing a circuit from trolly-wire a through the core h, a metallic tube m in which the cover slides and then as before through winding f, lamps c, d, winding g, and resistance u to earth. The signals are thus maintained after the trolly has left contact o. As the car leaves the section and closes the trolly-contact r, winding f is cut out (since both ends are now connected to wire a) winding g alone being energized, thus moving core h to the left, breaking the circuits and restoring the system to normal condition. As current through contact k ceases before contact is broken, arcing is avoided.