No announcement yet.

Polarity of track...

  • Time
  • Show
Clear All
new posts

  • Polarity of track...

    Probably any of you guys that race there can answer this question....
    What is the polarity of the track? I have a Slot it controller that I used on both of Mike's wood tracks a few years ago. I thought it was positive polarity, but just want to be sure.
    Thanks in advance,

  • #2
    If you have a typical plastic set track, it is probably negative polarity, unless you have changed it. Most custom built tracks are wired positive polarity.
    Matt B
    So. In


    • #3
      Here's standard Carrera Type B analog power track - which is this considered?
      Click image for larger version

Name:	IMG_7843.JPG
Views:	794
Size:	1.73 MB
ID:	39982


      • mattb
        mattb commented
        Editing a comment
        Carrera is negative polarity

    • #4
      The only 1/32nd set type track that is positive polarity is Policar. The polarity of a controller depends on which cartridge is installed, the cartridge is in the lower end of the case and the wires are connected directly to it. For older SCP01 controllers SCP01b is the regular positive polarity (Common Ground) cartridge and SCP01g is the high current positive polarity cartridge. SCP01c is the negative polarity (Common Positive) cartridge. The newer SCP0201 controllers use the SCP02g high current positive polarity cartridge or the SCP02bc dual polarity cartridge. The 02 cartridges work with the older style controller.
      If you find that you actually have the wrong cartridge it would be a good idea to buy a SCP02bc cartridge.
      Last edited by RichD; June 6, 2020, 06:50 AM.


      • #5
        Here is the Carrera terminal track in a schematic:
        Click image for larger version

Name:	E696B2E0-B803-435F-A7BB-32F8DEF78342.jpeg
Views:	819
Size:	1,002.2 KB
ID:	40018

        Converting to positive polarity is simple: just swap the + and - at the power feed on the terminal block. However, doing this will make the cars run in the opposite direction. To rectify, you need to switch the feed to the right and left rails of each lane.
        Click image for larger version

Name:	A4756A2C-868E-4CFC-9520-477E437B501F.jpeg
Views:	859
Size:	1.02 MB
ID:	40019
        Hope you can understand my drawings.


        • #6
          For ease of understanding, could someone state what positive and negative polarity mean in terms of what connects to the rails on the track? In the case of the Carrera powerbase shown, if it were turned over so the part with the connections (where controllers attach) was at the bottom, which way would a car go (left or right) if placed on the track? And, for that to happen which rail would be positive and which would be negative?

          To make the wiring super simple on both my routed tracks I mounted a Scalextric powerbase under the front straight and soldered jumpers going from its rails to the corresponding power rails (copper tape) on the track. On the oval to get cars to go in the US standard counter clockwise direction I think I crossed the wires coming up to the track, while on the road course they line up. Cars go right on the oval, left on the road course.

          The adjustable power supplies and Professor Motor controllers plug into the powerbases and I never gave polarity a thought.


          • slothead
            slothead commented
            Editing a comment
            WB2's drawings were posted while I was making the above post and I didn't see them. The drawings suggest the polarity is determined by which is connected to the rail on the left side of a car placed on the track.

            Are Scalextric, Carrera, Fly, etc. cars all made for negative polarity?

        • #7
          Hey thanks everyone. I was pretty sure I had a positive polarity cartridge, but there was no part# anywhere on the cartridge. It has been a few years since I raced at Cloverleaf and I just wanted to be sure. I have used the Slot it controller on my Carrera digital track with the digital cartridge since then. A couple years ago I bought a couple more analog controllers and modified a Carrera power track to test them. I ended up switching the lane wires AND one of the wires inside the box to get them to work. Naturally that was the hard way through trial and error. Lol
          Yesterday I wired another power track like WB2 shows in his post and it works properly too. It is simple, isn't it? Never my route though


          • #8
            Slothead, it seems to me that all of the different brands of cars I have had ran in the right direction out of the box. There was 1 or 2 of those same brands that didn't, but I attributed that to a mistake from the factory. And of course Carrera have the direction switch. I have not had a BRM,Revoslot, or Thunderslot, probably a couple others...


            • #9
              I'm in the process of designing a new oval track and am going to use my current Professor Motor controllers with it. If I follow my previous approach I'll get another Scalextric powerbase (or 2 if I make it a 3 lane track) and connect their rails to the copper tape on the track. At that point all I'll need to do is test which way the wires to the copper tape go to make the cars go counter clockwise.

              Since no one who'd ever be racing on the track would ever have their own controllers the ones I have will be switched between tracks as needed. No Red, Black, and White wired connectors needed, that's all managed in the stereo plugs on the PM controllers and inside the powerbase - plug and play.


              • #10

                This was taken from:


                The polarity reference is how the power goes to the controller, not the track.
                Search this site. There has been plenty written on the subject in the past.


              • #11
                With 1/32nd and 1/24th tracks the right hand rail is positive looking in the direction of travel. We should be thankful that all of the RTR cars in those scales stick to that convention. HO tracks have the positive rail on the left.
                Back in the '60s when you connected a track set you had to wrap bared wires around screw posts and tighten down the screws, so you knew where the wires were going. I imagine that a few people managed to hook things up wrong. Today polarized plugs are used to connect everything, often the power supply or at least part of it is built into a track section. That feature makes it faster to get your track running and eliminates the possibility of a misconnection. The downside to that is that it becomes more difficult to upgrade to better controllers and power supplies or change the track polarity.
                Be aware that a stereo plug creates a momentary short circuit when you you plug it in, that is one reason that they are seldom used with club style tracks. It may be short sighted to use non-standard controller connections. Here is a quote from the Slot Car Corner site:
                If you're a solo racer who never hosts races or participates in races hosted by others, you can probably get by without a controller hookup adapter. For everyone else, there's a good chance you may need a controller hookup adapter at some point to make your life a little easier. If you visit other tracks to race, the controller hookups may not match the connector on your controller. When you host races, other racers may want to use their own controller but the connector may not be compatible with your driver's stations.


                • #12
                  Unless the track is Carrera Digital in which the LEFT rail is positive. That's why the digital cars have the polarity switch on the cars.
                  Saginaw Valley Raceway
                  Only Rule: Just enjoy who you are racing with.