Thanks Dick. I have been running DCC for about a year and it does shut down very quick when there is a short, so I suppose that is the difference.Thanks for the answer and the good design advice. Regards... Peter Gagnon
----- Original Message ---- From: Richard Karnes <[EMAIL PROTECTED]> To: s-scale <[email protected]> Sent: Saturday, October 7, 2006 10:17:23 AM Subject: Re: {S-Scale List} Re: Turnouts and dead frogs Peter Gagnon wrote: > Could you explain why DCC needs special short circuit protections? It > would seem that the backs of metal wheels could rub against the open > point rail on a conventionally powered layout as well. Looks like the > probablility of such a short is determined by the wheel sets check > gause and the gap between the open point rail and the stock rail it is > near, a purely mechanical set of variables, so why the different > electrical concern in the case of DCC? Is it because DCC is more short > sensitive than a typical DC power pack or is there something else that > I'm missing here? I have a couple of Tom's Turnouts that I am about to > put into service on my DCC equipped layout, so I'd like to have a > better understanding of the issues. > Peter -- You are correct. It's the same thing. But with standard DC you have maybe an amp of track power, and the offending wheelsets generally glide through the brief short with only a hiccup -- if that -- and the train continues merrily on its way. But with DCC you have somewhere between 5 and 10 amps in the track at all times, enough to really fry electronics if you get a short. And it's enough to actually weld wheels to the track! So, in order to protect themselves, DCC systems self-protect by shutting down when a dead short is detected. I don't have a lot of DCC experience, but I discovered this at a friend's layout. He had to reset his system whenever a particular caboose with slightly out-of-gauge wheels went through the only turnout that he hadn't rewired/regapped. Dick [Non-text portions of this message have been removed] Th [Non-text portions of this message have been removed] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/S-Scale/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/S-Scale/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
