That coil of wire is called a variable resistor. One end is ground, the other end is positive and depending on where the wiper is in the middle is how much voltage is going out to the track. It would be measured on a DMM from the negative side to the wiper. When the wiper gets all the way to the end and you get full throttle, that’s the sign of the resistor being burnt up, and there isn’t much you can do about it. The design of the resistor will determine how many amps you can push through it. The more locomotives, the more amps, the more load the resistor will need to carry. The resistor takes ALL the current, and gives you some (how much depends on the setting) and turns the rest into heat. It may sound odd, but the slower you go, the more load is on the resistor, and thus the hotter it will get.
When supplying a low-impedance load on the wiper (therefore the coil resistance is fairly low as well,) tying one end of the wire coil to power, and the other end to ground would constantly draw power (and create heat) regardless of the load on the wiper (the track/locos.) More often, the non-powered end of the coil is left open, or tied to the wiper, depending on application and noise tolerance. Tying the non-powered end of the coil to the wiper simply creates a finite upper bound to the resistance should the wiper momentarily open as it is adjusted. When supplying a high impedance load on the wiper, the total coil resistance is usually much higher, and the non-powered end is tied to ground, since the load will not draw enough current to drop sufficient voltage on the coil.
Finally I’m done with the wiring… well all but an extension harness and power harness that are external, I’m done with all the internal stuff. Here is the underside of the 2 entrance module, and the ladder module. The last 2 are nothing really special, they just have jumpers between the modules. Here is the entrance module This is the ladder module, quite a bit more going on here, but you get the idea. Oh and this is the “master” module as it has the external control harness to it. And here is the control box plugged in.
On my workbench, a few hundred locomotives being entered into the ESU Cab Control system. Also seeing which units are still working and which units aren't. I have a lot of failed Digitrax decoders (88) thus far.
Well… looks like I almost succeeded. With all the routing of wires and getting everything hooked up, I only screwed up one thing! It was due to the control panel being upside down when I mapped it out, and you would have thought I got every button on backwards, but I only got one in the wrong spot… which yes does put them all in the wrong spot, but they are all in the right order at least. I will simply have to open the box and move a couple of the ports and all will be good. Not bad I think. When addressed and via loconet the DS64s operate correctly, but they are not operating on track power alone, not sure if it’s a setting on the DS64 or something else, I’m looking into that now. They do power up on track power, but they are not accepting commands from the rails. I have also tried with external power as well, still no joy. I will keep digging.
always one lil thing hahah i like the modules pretty cool to see how everything is done. Thank you for sharing.
That one little thing turned out to be much simpler than I originally thought. Once I flipped the modules over, and hooked them up together I tried to see what was what, make notes and then change what needed to be changed. I found the issue with the DS64s not wanting to get signals through the rails, it turned out I had the BWBW set to WBWB on the second module and that was causing a short that when the modules were not connected rail to rail didn't trip the command station's short protection, but did mess up the communications. Swapped a couple wires and I am now good to go. Then I discovered the real issue with the push buttons. Only 2 were wrong, and they were the 2 from the entrance module... curious, when I say SW1 the correct switch throws, when I say SW5 the crossover throws, but it's opposite when I push the buttons. Flip over the module and there I see I plugged in the wires into the wrong switch inputs in the DS64, easy fix. Now everything works as it should and exactly how I intended it to!! DC mode works perfectly as well. Next up, I need to make cuts in the rails to kill power to each leg. I forgot to add the black rail joiners before the power tracks, so now I have to cut stuff. Oh well.
AH! Think I've solved my BLOWN-UP transformer/FRIED slot-car controller aka overall throttle problem. Upon switching to batts I had an epiphany -> "why not rob & use the pulse width modulator that was part of my hydrogen generator"? Turns out 24v was too high with the train still jumping immediately to warp speed but 12v works just fine with much more low-speed control and, as a bonus, kids just love the "speedometer". I suspect 18-20v would be perfect (go figure isn't THAT what most HO transformers do?) Am using 'this controller here' and see no incompatibilities with my other standard Tyco transformer. Attached is pic of my current "testing mess" note the '000' & easily mountable twist throttle and directional/neutral switch (which am not using finally figured out how to wire the Atlas Controllers) (ps: As far as I know, so am told, my two new Walthers DCC locos don't have decoders installed and the Atlas/power pack directional switches work as intended BUT WHY IS IT when I end-over-end (ie: reverse) the position of the train on the track IT STILL GOES THE SAME WAY? In spite of intro post (my bad which links to 'O" scale) my exact model is here . . . is it the "alternating current traction motors"?)
20v is way too high in N scale. That’s more of a G scale voltage. N scale works just fine around 9v to 14v and most of the time on DC an N scale engine will usually start moving around 3.5v, and will reach top speed around 12 to 13v.
Final report on the station modules. Electrically they are finished and everything is now 100% functional. So it wasn’t without problems, when I got all 4 modules together I discovered a short which was in the extension module. I just didn’t watch the white and blues, I just assumed they were all in the same order. Easy fix, just swapped the wires on the terminal strip… all good. I tested the power cut offs… all good… tested the push button controls for the turnouts, all good. But I did find one little oddity. When all 4 tracks are powered up the #3 switch keeps cycling every few seconds. Turn off power to track 3 or 4 and the issue goes away. This only happens when the power is on all tracks. If 1 and 2 are off it doesn’t do it. I’m guessing a short somewhere but I’m not sure where, but I think I know the cause, I will confirm when I open the box up. Well that’s it. I will be working here soon on the scenery, and current plan is to make the new city’s road match up to the road on the Route 66 modules so they will flow together if I ever get to link both sets end to end. There will be a station and platforms, the platforms will go to near the end of each full run, the station will cover a good chunk of the tracks on the last module, I’m thinking a few truss style arches are in order. Stay tuned for that.
Ok thanks! New problem! I bought most all track & switches second-hand does one actually need to lube switch machines? While at 1st try "not working at all" (grrr to those ebay sellers desperate due to our deathly economy) I discovered if I applied more throttle aka 'volts' they are fine so is independent power for accessories SOP? Am assuming DC not AC correct? I've ordered more PWMs but perhaps I'll have use for that 'ole Tyco transformer after all? And is most scenery lighting AC (?) or does it not matter, either/or, as I do notice the AC tap on the Tyco. *sigh* after exchanging the active switch out for another NOW I suspect the replacement switch, due to engine dead STOP, has a bad connection on one of the turnout rails (grrr to sellers again)? Sorry so many DUMB questions NO MAJOR SHORTS YET! (ps: used an approx 15' length of thin 20/gauge solid wire for conx to house batteries for power with a similar MidNight Solar breaker inline . . ) (pss: disclaimer a sexist joke -> "Doctors used to hold newborn babies up by the ankles before slapping them on the arse but do you know why they can't do that anymore?")
Well revisiting the little 4.5 volt diesel center cabs by TGW. I finally gave up on trying to convert these to run on 12 volts. Way out of my knowledge base and also equipment. However I do have a mechanical limiter that I devised for my power pack that prevents me from exceeding 4.5 volts along with a digital voltage meter attached to the power pack so I can monitor the voltage. So I can lock my power pack at a max of 4.5 volts and run the little 4.5 volt equipment all day. When I want to run the regular voltage I just flip the locking lever off. Anyway trying to run these locos on my unitrack layout they kept hanging up and derailing at all the turnouts. After careful observation I suspected that the side rods and the rod drive with the counter weight were hanging up going through the turnouts. Very tiny wheels on these critters. So I bit the bullet and removed both the drive rods and the drive wheel for the rods with the counter weight knowing I would play hell trying to put it all back due to loss of hand dexterity and eyesight, not to mention old shaky hands. Pictured below is a shot of one with the drive rods removed on the right and the other with them still on on the left. 100_0001-1 by John Moore posted Feb 18, 2023 at 10:00 AM Notice the left one with the drive rods down. Right at the bottom of the tiny wheels. While I had the shell off on the one I managed to get a bit more thin sheet lead in the shell. On the layout finally getting through the turnouts but the running performance is still not great so pretty much have decided these are a bust.
Wanted to hit the 'like button' but since they might be considered a bust didn't know if that would be misinterpreted but do 'like' the effort you put into all of your projects and the willingness to go down new roads. Sumner
The main problem these suffer from is the drivers are too small. The exposed gears on the bottom of the drivetrain are about the same distance as the wheel surface to the track. One mm larger of wheels would let the drive rods and the gears clear everything. So these will set until I either find a new mechanism to put under them or a slightly larger wheel that can be pressed on.
I may be close to an answer to a mechanism for the little critters. The TM-TR02 it is a Tomix or Tomy Tec two axle chassis with a small 12 volt motor. So one is now winging its way from Japan.
