i replied to an existing thread that has had some views in the last few hours without any responses, so ill try to post here , below is the question and this is the thread i replied in earlier.
please post more on the ways on how to switch the polarity , i am trying a simple reverse loop with a wye connector, like the drawing of the hangman’s noose above.
i came upon a short circuit, then i seen the rails when back on themselves. i quickly disconnected and started my research
im also using DC only
i have some isolating connectors on order, they might take awhile, i live 400 miles from the store i had to order from.
do i isolate the wye connector from the rest of the rail?
Believe me, it is quite straightforward. Look at the wye from the base running across it…the segment that is part of your main line. You look up and see the two sides meet and form a tail. You should gap either the left or the right side of the triangle between the two turnouts affording access to the side you choose. Pick one side of the triangle and gap each end. Then, wire it separately via either a DPDT or an auto reverser. The power can still come from your base controller or the bus, and it doesn’t matter which wire goes to which rail, as long as you can control the polarity to make it match the polarity of the segment the train is leaving.
If you don’t have to alter the polarity when it enters that segment, then you know you will have to alter it before the engine leaves that segment. That’s the whole point…at one end it won’t match unless you or the reverser corrects the inevitable mismatch.
Are you talking about a “reverse loop,” in which the train continues around a loop and ends up going in the opposite direction, without stopping or backing, or a “wye,” where the train does what they call a 3-point turn in driving school? They do the same thing, but it’s just a bit easier to describe where the insulating joiners go if we know which track plan you’ll be using. (The confusing item is that a Y-shaped turnout is sometimes also referred to as a “wye” turnout, but in itself it does not constitute the same thing.)
yes i am using wye to create a reverse loop, to got back the way the train just came from, similar to a hangman’s noose, in the above or below link someone drew a sketch, that is exactly what i have going on.
So if I understand you correctly, you do not have a wye as in three switches in a kind of triangular arrangement, but the wye is just the single switch you use to make the loop. If so, you want both rails on both legs of the turnout insulated at the end of the turnout. Either the isolated loop of track or the rest of the layout has to be fed through DPDT switch wired to reverse the polarity. If you wire the loop through the DPDT, then you have to stop in the loop, then throw the DPDT and switch the direction on your power pack before continuing through the other side of the turnout. The advantage to this method is the direction switch remains consistent on the main part of the layout. If you wire the rest of the layout through the DPDT switch, then you do not have to stop in the loop, you just throw the DPDT switch while you are in the loop and you can continue on out the other side. The downside to this method is the direction switch on the power pack will not be consistent on the main part of the layout - every time you throw the DPDT switch, it swaps the meaning of the direction switch.
How are you controlling the turnout? The reason I ask is because if you are using a remote method to control the turnout, it is a good idea to have whatever controls the turnout also control the DPDT switch(the DPDT switch does not have to actually be a switch, it can be a relay or set of contacts on a Tortoise switch machine), because to go through the turnout, the DPDT switch setting has to match the turnout setting.
How do you currently control train direction on the rest of your layout? Are you using a direction switch built into your power pack? Is there one on your cab control? Or do you have something like one of the Atlas slide-switch boxes with 2 positions and a center off? Or is it just a toggle switch you’ve bought and wired into the circuit?
Basically, you’re going to wire up another one of these that just controls the reverse loop. Insulate both rails of both paths of the turnout at the frog end. Wire the control toggle (it’s a double-pole, double-throw (DPDT), center off toggle) to the loop.