| 摘要 |
PURPOSE:To safely and readily remove ice and snow by Joule heat which is produced by short-circuiting trolley lines for feeding current to a travelling vehicle therethrough when ice and snow are to be removed, by connecting a power feed controller provided with a change-over switch to one end of each of the trolley lines and a trolley line short controller to the other end. CONSTITUTION:For removing ice and snow which are stuck to and accumulated on trolley lines 1 in winter or other cold weather, a change-over switch 7 is changed over to close a limit switch LS. A no-fuse breaker 11 is then thrown in before an ice and snow removal starting push-button switch 13 is turned on, so that electro-magnetic contactors 10, 17 are excited. Since normally opened contacts 10a1-10a3 and 17a are closed, the electro-magnetic contactor 10 holds itself and an on-delay timer 14 is excited to short-circuit the trolley lines 1. On the other hand, a power is supplied from a power supply via a terminal 5, a power supply convertor 9 and a terminal 8 to the trolley lines 1, that is, a current flows through said trolley line in the form of a short-circuit current, thereby generating Joule heat by the internal resistance aganist the current to melt the ice and and snow. there is a lapse of a certain period before a contact 14b is opened to complete the removal of the ice and snow. |
