Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!dimacs.rutgers.edu!bcm!convex!mic!letni!rwsys!kf5iw!k5qwb!lrk From: lrk@k5qwb.lonestar.org (Lyn R. Kennedy) Newsgroups: sci.electronics Subject: Re: Traffic signals Message-ID: Date: 20 Apr 91 22:48:07 GMT References: <11928@exodus.Eng.Sun.COM> Organization: Radio Amateur k5qwb Lines: 31 bender@oobleck.Eng.Sun.COM (I want to be eating rich soup in another town) writes: > In article lrk@k5qwb.lonestar.org (Lyn R. Ke > ->One posting mentioned a system truning the lights green both ways > ->when two emergency units approached from different directions. I > ->hope they fired the guy if this is true. Traffic lights are supposed > ->to have a safety device that monitors current to the opposing greens > ->and if both are on it shorts the power line, forcing the system to the > ^^^^^^^^^^^^^^^^^^^^^^^^ > really? you mean it literally shorts the 110VAC coming into the traffic > light controller? I assume then that some traffic engineer has to come by > and reset the controller?? > > ->flashing mode. That's the way it was explained to me. I don't repair these things but it's supposed to have a basic controller to do the 'flash' mode and then another box to run the 'colors'. You can un-plug the controller and re-place it by putting the system on 'flash'. If the fuses to the controller blow, the switch to the 'flash' mode should occur. Since the 'opposing greens' is so dangerous, the safety device blows the fuses ( maybe breakers? ). ------------------------------------------------------------------------- lrk@k5qwb.lonestar.org lrk@k5qwb.UUCP 73, utacfd.utarl.edu!letni!rwsys!kf5iw!k5qwb!lrk Lyn Kennedy K5QWB @ N5LDD.#NTX.TX.US.NA P.O. Box 5133, Ovilla, TX, USA 75154 -------- "We have met the enemy and they are us." Pogo -----------------