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  • Jumper tracks???

    Hi SCI fam.... Happy memorial day, I am putting together Greg Braun's "Whitewater Farm 65" I realize that jumpers will be extremely beneficial. .. I was wondering if I use some terminal tracks with a power source plugged in, would that serve the purpose??? Gonna try it anyway, but I still have to clean all the tracks ect. So if anyone has had success with terminal tracks as jumpers, let me know.

    Keep it in the slot
    tdady216

  • #2
    Jumper track (Dukes style) vs. track jumpers.

    I don't think that's how it works. I think there needs to be a link to the controller.
    Start with one power supply per lane, so a two lane track needs two terminal tracks, and two supplies. This keeps two cars from sharing one supply.

    You could install a second terminal per lane and jumper both the supply and the controller leads to each one.

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    • #3
      Yeah...I am pretty sure your right, I have soldered some jumper tracks in the past. ..want to be lazy.

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      • #4
        Oops
        Last edited by tdady216; 05-29-2017, 04:01 PM. Reason: Repeat

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        • #5
          I don't think you can gang up two power supplies like that, though.
          Maybe. Just jumper the controller. I dunno.

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          • #6
            I have used AFX track but I cut the common connection to both slots on the power track so that each lane could be provided with individual power. By using multiple power tracks (which makes for multiple driver stations) I could solder jumpers to each one coming directly from the transformer. This set up gives nice smooth power all the way around.

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            • #7
              You can add jumpers without having to solder anything using this method: https://drive.google.com/file/d/0BzL...ew?usp=sharing

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              • #8
                Thanks guys.. Probably won't be till the weekend to get started.

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                • #9
                  Originally posted by MotorHead View Post
                  I have used AFX track but I cut the common connection to both slots on the power track so that each lane could be provided with individual power. By using multiple power tracks (which makes for multiple driver stations) I could solder jumpers to each one coming directly from the transformer. This set up gives nice smooth power all the way around.
                  yes, this isolates the lanes from each other.

                  you can still use the extra term tracks, but run the wire from the term track with the controller/PS to the additional term tracks

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                  • #10
                    Cool idea but Solid wire for dc current?

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                    • #11
                      If I remember right
                      DC will use the complete wire and AC will use the surface?
                      but the effects for current of stranded vs solid is really the same. Stranded is just easier to bend

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                      • #12
                        That surface effect is mostly confined to radio frequencies I believe.

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                        • #13
                          frequencies do play a part, and relate to how deep on the surface it travels.
                          But the gist is that it is the AC current not DC that runs the surface.

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                          • #14
                            Originally posted by slotking View Post
                            frequencies do play a part, and relate to how deep on the surface it travels.
                            But the gist is that it is the AC current not DC that runs the surface.
                            I stand corrected< I thought it was the other way around. I was only recently told about the surface thing by a friend, maybe he not so smart after all? LOL!

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                            • #15
                              when elecrons migrate to the surface of a conductor, etc.

                              Gentlemen,
                              the 'skin effect' starts at 30-300 kiloHertz, depending on what percentage of the total power one considers to begin to become relevant. as an RF guy, for me that's pretty early, and that low frequency is also above anything that DC slotcar motors draw in the way of any significant current flow. and yes, since I design my own controllers (and wire lots of tracks) I have researched, investigated, measured and experimented with it at length to make sure that I didn't miss anything, all the way up to high-end cobalt motors. just in case I could find some small advantage.
                              I've said this before, and i'll say it again: regarding the skin effect with slot cars, believe me, I tried. the math doesn't work, nor does the practice, for the skin effect- even one gauge of wire bigger or slightly better contacts blows it away.


                              btw, it also turns out that a stranded conductor doesn't really buy one much at the higher frequencies anyway- it just acts like a lumpy single conductor with a little more surface area, and it also costs you some loss in an RF transmission line because it's not a smooth surface. pretty much the only place one finds it in the RF world nowadays is in deliberately flexible cable, such as LMR-400-UF (ultraflex) or RG-400, the stranded center cond. version of -142. both of those have slightly higher loss across frequency than their solid-center-conductor counterparts by spec and also on the network analyzer (and flexibility aside, are also a pain in the butt to put a center pin on as well). higher power coaxial RF cable like LMR-900 uses a hollow tube for a center conductor (because of the aforementioned skin effect) and has a corresponding foil shield outside the dielectric for roundness underneath the outer braid. being a concentric tube-like tunnel is an important characteristic at RF frequencies, which stranding does not meet. but I digress. we're not really talking rf here.

                              stranded wire as a track contact is a different animal, as it provides multiple contact points. that's not frequency-related, though, rather point contact/ wetting/ sliding DC resistance.
                              for qualifying in wing cars, we used to use solid-cond. enameled magnet wire for lead wire because it was lighter- it didn't matter that it wouldn't last a race; it was replaced after qually.

                              for track wiring, it's the gauge of the wire (cross-sectional area) that counts, as well as good connections, and whether or not solid wire would be too annoying due to its relative inflexibility compared to stranded or be prone to cracking and subsequent breakage at sharp or repeated bends near or at the termination point where the insulation does not provide support.
                              I usually use stranded wire for DC circuits because it's easier and flexible, although when wiring big tracks, a lot of big-box store solid conductor house wire is cheaper. but one has careful how it is terminated. crimp lugs work well with either, as does wrapping the solid conductor of a long 10-12 AWG feed wire around a protruding screw on a nice big central terminal board when using multiple feeds. but this sounds like overkill for what you asked about.

                              bottom line, you can use whichever type makes it easier for you without worrying about any high-frequency stuff- that's irrelevant.
                              speedy
                              Last edited by Speedynh; 06-07-2017, 05:52 PM. Reason: fixed a couple words

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