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Single track routed loop

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J

· Bill
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#22 · (Edited by Moderator)
I did a single lane double reversing loop a while back. There was a long thread on it, but here's some photos of the technicals and the track. It required some tricky wiring and a couple of relay switches. I began with information from the hillclimb on the Old Slot Racer site (but this was only a single reversing loop and I wanted a double reversing loop so that you could go round n' round), then got more information from Ausslot forum where someone had posted some technical drawings. I modified these technical drawings with help of people on SF and Ausslot (and some trial and error). I'm not sure I still understand the technical diagram, but it made sense after I worked with things for a while. It did take some trial and error to get all the electrical working correctly, but it wasn't that hard and a very interesting challenge. The track was eventually purchased by Nomad Slot Car Racing where they use it for rally trials.






THE RELAY (I used the one


THE BUILD








 
G

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#23 ·
QUOTE (Pete-slot @ 22 Jul 2010, 16:39) <{POST_SNAPBACK}>have a look here for a reverse loop automatic solenoid switching device
http://www.guidetozscale.com/html/solenoid_devices.html
the switch is automatic , small and its Marklin so its bound to work for years without fail.. good solid german stuff.
cheers
Peter
Marklin have a good reputation, so you'd expect their relays to be reliable when switching the currents they are designed for.
That web page says are intended for use on Z-Scale model railways. This is a very small scale, and the motor currents are similarly small. Even the motors used in the larger 00 and HO model railways are very much at the low end of the currents used in slot car motors.
Most 1:1 car accessory shops stock relays for jobs like switching driving lights, those are more suitable for the higher current many slot car motors will take.
 
biedmatt

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#24 · (Edited by Moderator)
What you want is a dual coil latching relay. This relay has a coil that switches it to one side and a second coil to switch it to the opposite side. It will remain in place without power to the coil until the opposite coil is energized to switch it back, hence the designation "latching" With this you can use two dead strips at each loop. One dead strip trips the relay one way and the other dead strip trips it the other way. Since it remains in position, it's perfect for momentary voltage impulses like a dead strip. It must be a double pole double throw relay too so you can wire the track voltage through the contacts and reverse the polarity of the track voltage for your car to run in the opposite direction. I can get you a maker and part number when I'm home tonight. I have one specifically to do a routed track as you have described. You will only need this one relay to make it all work.

Here's the specs on one. If power is applied to the operate terminals 2 and 10 it will transfer and hold position. If power is applied to the reset terminals 3 and 6 it will transfer back and hold position. The switch for "operate" and "reset" is your dead strip at each loop. Wire the track power through the contacts to reverse the polarity. This has a 24VDC coil, you want 12VDC. I'll have that info tonight.

http://www.automationdirect.com/static/specs/755relays.pdf
 
biedmatt

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#27 · (Edited by Moderator)
A wiring diagram showing how it all goes together.
Don't know why it won't let me paste the image, here's a link to it:
http://i887.photobucket.com/albums/ac74/bi...versingloop.jpg

Link to the specs for the relay:
http://www.magnecraft.com/library/section7/105A_755.pdf

This will allow you to constantly run through each loop without having to press any switches to cause the polarity reversal. The relay will change state at each dead strip just as your car crosses over it.

Only one relay is needed. Place the two dead strips, one at the end of each reverse loop, just before you (re)-enter the main road.
 
biedmatt

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#32 · (Edited by Moderator)
QUOTE (TransIssues @ 24 Jul 2010, 15:31) <{POST_SNAPBACK}>Matt,

Cool! One question though, no brakes? And would you mind confirming the color of the wires from the controller (assuming positive polarity)?

Thanks!! Might just build a rally track this is so cool!

Cheers!
Paul

Brakes and all will still work.

Use this supplement diagram:
http://i887.photobucket.com/albums/ac74/bi...ysupplement.jpg

With the diagram previously posted:
http://i887.photobucket.com/albums/ac74/bi...versingloop.jpg

...for the whole shootin' match. Color codes for the wires were arbitrarily chosen to just keep it easy to follow, but I did use the same color code for both diagrams. I made it two diagrams so you could print it on 8.5"x11", yet still keep it legible. Everything but the dead strip wiring is shown in the second diagram.

Just to keep all the info in one post, here again is the link to the Magnecraft #755XBXCD-12D relay specs:
http://www.magnecraft.com/library/section7/105A_755.pdf
 
J

· Bill
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2,880 Posts
#33 ·
QUOTE (biedmatt @ 24 Jul 2010, 04:19) <{POST_SNAPBACK}>$100 ("$49.95 per end") vs $20 and two devices to wire instead of one. Not what I would call "easiest".
My single lane double reversing loop track required two latching relays (see above) -- not one. Each one cost about $12 (USD) as I recall. I am also "electrically challenged" so making sense of the wiring diagrams took a lot of studying and thinking and questioning. Once I had the diagrams, it was just a matter of "connecting the dots" -- that is, hooking of the wires according to the diagram. It did take some time to figure out, and it helps to figure out how and why it works, but in the end I understood it. That said, it would take me some time to make sense of my diagram now (two years later). The problem with the Old Slot Racer diagram that I began with was that is was a single reversing loop -- that is, you got to the bottom and the race was over -- this is much easier to wire (then you'd only need one relay to reverse polarity). I wanted to loop back and continue racing (that's where the wiring got tricky for me).
 
biedmatt

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#34 · (Edited by Moderator)
QUOTE (jmswms @ 25 Jul 2010, 10:01) <{POST_SNAPBACK}>My single lane double reversing loop track required two latching relays (see above) -- not one. Each one cost about $12 (USD) as I recall. I am also "electrically challenged" so making sense of the wiring diagrams took a lot of studying and thinking and questioning. Once I had the diagrams, it was just a matter of "connecting the dots" -- that is, hooking of the wires according to the diagram. It did take some time to figure out, and it helps to figure out how and why it works, but in the end I understood it. That said, it would take me some time to make sense of my diagram now (two years later). The problem with the Old Slot Racer diagram that I began with was that is was a single reversing loop -- that is, you got to the bottom and the race was over -- this is much easier to wire (then you'd only need one relay to reverse polarity). I wanted to loop back and continue racing (that's where the wiring got tricky for me).

Bill, your track works perfectly. I've seen the video. What is nice about my circuit is it uses a relay that is so perfect for the application, you could almost think it was originally designed for the job. Only one relay is needed, the wiring is far simpler and the relay is only enrgized for a moment instead of being on 50% of the time needed to complete a circuit of the track. I like simple when it fits the application because simple seldom fails and when it does, it's simple to fix. I posted this (less diagrams) over at SCI when you were making your track, but "thatguy01" (poster's handle) had you so far down the road with his diagram/circuit that there was no way I could persuade him to bring you back.
http://www.slotcarillustrated.com/portal/f...mp;postcount=61

The $100 dollars I comment on and you reference is not a description of your relays, but Injectormans model railroad device.
 
biedmatt

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#35 ·
biedmatt

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#36 · (Edited by Moderator)
Bill, I took another look at your diagram, now I think I understand the confusion. The relays you describe as "latching" in post #33, first sentence, are not really latching relays. The relays are described in the lower left corner of your diagram as '"regular" (non latching)'. This is a correct description of your relays. Relay #1 in your diagram is wired to latch itself by switching power through the contact marked A and back to the coil of relay 1. When relay 1 is energized by a car crossing dead zone 1, contact A closes and keeps power on the coil of relay 1, thus holding it energized. Now you need to turn off the power switching through contact A so relay 1 will de-energize so a return run by the car can be made. This is done by momentarily energizing relay 2 when the car crosses dead zone 2. The power holding relay 1 energized via contact A is turned off when relay 2 contact A is momentarily opened, causing relay 1 to de-energize. The cycle repeats when dead zone 1 is crossed again by the car. So while your relay 1 is wired to latch, it is not a true latching relay.

Relay 2 in your diagram never latches. There is no return to the coil of relay 2 with power switched through a relay 2 contact. It is simply turned on when a car crosses dead zone 2 and then de-energizes when the car exits dead zone 2.

The relay I have in my diagram is latching because it will hold state even after power is removed (perfect for a momentary contact like a car passing a dead zone) and without the need to switch power through one of it's own contacts and back to it's coil as you do with your relay 1. This "holding of state" without constant power to the coil is why it is so perfect for this application.
 
Brit Slot Nut

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#38 ·
Hi Guys and most especially Matt,

Thanks again, I get the gist of what is going on, but the firewall at work is killing all of the pictures. I will have a look when I get home.

I am looking forward to getting this up and running in the summer. New thread alert!

thanks

BSN
 
biedmatt

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#40 ·
QUOTE (Brit Slot Nut @ 27 Jul 2010, 08:12) <{POST_SNAPBACK}>I am looking forward to getting this up and running in the summer. New thread alert!

thanks

BSN

Looking forward to your new thread. I'm planning on starting mine this fall now that the main track is where I want it. I liked what Bill had done with his and it's a nice size layout so I thought I'd give it a try.
 
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