Hello,

Robyn has completed a preliminary design for her garden railway, but it includes a reverse loop.

The manual (user guide) that came with the set shows how to wire the loop using a relay so that it does not short when returning to the mainline through the turnout (we don't own one of these yet)..

Does the approach shown in the manual work with delta and digital?

How does the relay trip so that the track polarity is reversed??

As you can see I have been spoilt by the three rail HO.. This is much harder...

Adrian

Adrian

Some of us spoilt with 3 rail system.

With 2 rail, reverse polarity can be overcome using a module. this will depend if you want to use in conventional operations or digital.

Lenz has a product and this is to be used only for digital operations. I have file on this.

Cheers

Noel

Noel and Juhan,

The picture from the manual is:



It looks like I have to press the button at just the right time for the polarity to reverse..

Adrian

Edited by moderator 10 January 2011 20:34:16(UTC)  | Reason: Not specified

Adrian,
You might want to recheck the schematic of the manual, it`s wrong.
Each of the SPDT switches of the relay must be hooked up to one brown and one red wire.
The center wires of each SPDT remain connected to the loop, as is.
Connect the red wires to the outer terminals of both SPDTs and the brown wires to the inner ones or vice versa, in order to get the intended polarity change in the reversing section. As proposed by Noel, hook up the turnout and the relay in parallel to simplify operations.
Also move the isolation gaps closer to the turnout to operate longer
trains.

Note: Only one end of a reversing section and the respective isolation gaps my be bridged at any given time.

Another note: The basic scheme is okay for Command control, such as
Maerklin DELTA/Digital or DCC. In addition it works for analog AC operation but not for analog DC. Analog DC operation requires different and more complex circuitry, depending on your needs.

Best regards,
Manfred

Sorry Adrian

The 8947 cannot be used as the maximum volts it can carry is 10 - again my apologies.

Shall do some more research and get back.

Cheers for now


Noel

Noel,

We are planning to use the IB on the 1 gauge layout. On the basis that there will (eventually) be more than one lok and we won't run the HO layout at the same time as the 1 gauge. Does this change the design of the loop?

BTW Is your e-mail giving trouble? I can always seem to send, but the mail is taking 2 or three days to arrive..

Adrian

I really can't see what the 3rd pair of 56091 (down at the turnout) is there for. It should be sufficient to have only one isolated track section, the upper half circle in the figure. While the train is on the isolated section, you reverse the polarity to it (unless you are using DC, then it becomes more difficult).

The 7244 + 7272 solution should work with digital too, and it should be OK to have several locos running, but you can not have one loco entering the isolated section of a loop while another one is exiting it and you can not have two locos entering or exiting the loop at the same time in different directions.

The 7244 + 7272 solution is manually operated and you have to be sure you operate it correctly to avoid shorts when the locos enter and exit the isolated loop section. I have no scale 1 experience myself and I don't know how to detect train movements, but if you have a method for that you could make the reverse loop automatic.

An automatic solution would need one 7244 and four contacts. You put two contacts to the left, one inside and one outside the isolated section. If any of these two contacts is activated, the 7244 is activated as with the green button of the 7272. Two contacts are placed to the right, one inside and one outside the loop. If any of these two contacts is activated it corresponds to the red button.

The stop makes sense.. It needs to prevent a short that might occur if the wheels bridged the two isolated sections.

How does this work with digital? It's not like an isolated HO section that is serviced by a booster.

(I know I can test this myself, but everything is still in the box until the planning is completed)... Does the Maxi reverse direction when the track polarity is swapped?

This two rail stuff is very complex.. I'm off to the HO layout before my head hurts too much..

Thanks everyone.
Adrian

Noel, Adrian,
Try to answer these questions for yourself.
1)Where does the track section, leading from the straight leg of the turnout to the left side of the loop, get its power from with the third pair of insulators installed right after the straight leg of
the turnout.
I would say, it`s never powered at all, regardless of the position of the relay contacts.
And, in case the left and center contacts of each SPDT are connected,
the reversing section isn`t powered too.

2)"Remove" the above mentioned insulators.
Now, I would say, the above mentioned track section IS powered.
Take a close look at the feeder wires from the tracks to the relay terminals.
Both of the red wires come from the left rails to one SPDT.
Both of the brown wires come from the right rails to the other SPDT
of the relay.
Will this installation change polarity in the upper hemispheric reversing section?
I would say nope.

Regards,
Manfred