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Discussion Boards => HO => Topic started by: jimdavis88 on February 20, 2020, 12:25:03 PM



Title: Reversing loop question
Post by: jimdavis88 on February 20, 2020, 12:25:03 PM
I watched the Internet on how to do a reverse loop. First; put insulating rail joiners on all four tracks, I got that part, then wire in the polarity reversing module. My question, after the put on all four insulating joiners, can't I just run a new power lead to the now dead section of track (the loop), instead of using the expensive reversing modules?


Title: Re: Reversing loop question
Post by: Trainman203 on February 20, 2020, 01:42:25 PM
Sounds like you are isolating the track, but restoring the same current problem with wires instead of rail joiners. You arenít switching polarities which is what the reverser does.


Title: Re: Reversing loop question
Post by: Hunt on February 20, 2020, 06:58:26 PM
. . . My question, after the put on all four insulating joiners, can't I just run a new power lead to the now dead section of track (the loop), instead of using the expensive reversing modules?


 Click Here  (http://www.azatrax.com/model-railroad-reverse-loop.html) the information should help you understand why what you are think will not work.


You failed to state if you are using DCC or DC power on track.

Most automatic reverse loop modules work only with DCC.

You can use a much lower cost DPDT toggle switch for either DC or DCC to manually control the track polarity

 


Title: Re: Reversing loop question
Post by: RAM on February 20, 2020, 10:53:07 PM
Correct me if I am wrong.  On DC your would need two DPDT switches.  One for layout and one for the reversing loop.  Then you would not use the directional switch on the power pack.
on DCC you would only need one.


Title: Re: Reversing loop question
Post by: jward on February 21, 2020, 11:58:20 AM
On DC you only need one DPDT switch wired into the reverse loop circuit. You can use the direction switch on your power pack for the other. You have to flip both direction switches at the same time though.

There are a couple of other ways to wire this on DC. The easiest is to wire a bridge rectifier rated for at least 3 amps where you would put the DPDT switch. Wire the DC side to the track, and the AC side to the power pack. The rectifier will keep the train running the same direction regardless of which way the direction switch on the power pack is thrown. So you just change the direction switch while the train is in the loop and when it exits it will continue on as usual. The only drawback to this method is that your reversing loop effectively becomes a one way track, as the rectifier will prevent you from running the other direction through the loop.

Another method, which works on both DC and DCC, is to use a relay wired in parallel with the switch motor to change the polarity in the loop. This works best if you enter and exit the loop through the same switch. It is also great for stub ended tail tracks on a wye. The relay contacts are wired in place of the DPDT switch, in the same configuration. This method automates the loop, as the simple act of throwing the track switch changes the polarity of the loop. Thus you can never enter the loop the "wrong way" and short everything out. Once again, you will need to flip the direction switch on the power -ack while your train is in the loop.