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How To Wire A Slot Racing Track

In ancient times alchemy was pursued in hopes of turning ordinary lead into not so ordinary gold. That same level of mystery, secrecy and folklore seems to shroud the the far simpler science of electrical schematics and wiring polarity of toy cars. One byproduct of the Professor Motor foray into the electronic slot racing controller business has been the somewhat difficult task to provide proper wiring instructions for the great number of possible ways that slot racing tracks may be wired and to support frequent emails and phone calls related to this topic. Just as difficult is the need to understand that issue globally since a great number of our controllers are exported overseas.

So, how should wiring best be handled if one is starting from scratch on a new track, or trying to deal with an existing track and increase the size of the layout substantially? Another challenge in this is hooking up a polarity sensitive controller such as the Professor Motor electronic unit. The best way to handle all this is to follow the following schematics and, if questions or problems, give us a shout. First off, all of the following discussion will assume that the car itself is wired such that the right hand braid of the pickup shoe (considering direction of travel) is positive power. Most places in the world that scheme is used including almost all of the 1/32 home set cars. An easy way to check this, if you need to, is to get a couple of flashlight batteries and some wire and hook all this up to make the car go (a little help spinning the rear axle may be needed). Since the batteries are clearly marked with the positive (+) terminal this simple diagnostic should be able to unravel any confusion on that point.


Wiring Using The Professor Motor "Wiring Centers"

After much customer feedback on track wiring issues the PMTR1072 (2 Lane) and PMTR1071 (4 Lane) Wiring Centers were developed to provide a much simplified and bulletproof way to provide complete electrical protection for a 1/32 or HO slot racing track. Each of these gadgets includes a series of all-electronic self-resetting circuit breakers and is adequate to provide electrical protection against short circuits and overload conditions that may occur due to misconnection of a controller, foreign material shorting out the track or any other issue in the car, controller, or track system. At the same time, the circuit breakers will allow 6+ amps per lane to enable high performance motors to be run if desired.


Using The PMTR1071 4 Lane "Wiring Center" 

To connect the PMTR1071 use the wire terminals that come in the kit & solder wire (16 gage wire PMTR1015 would be recommended) to those terminals before connecting using a good grade of electrical type solder (do not use acid flux or acid core solder). Wiring schematic for a 4 lane track layout is shown in this schematic : PDF 


Using The PMTR1072 2 Lane "Wiring Center" 

To connect the PMTR1072 use the wire terminals that come in the kit & solder wire (16 gage wire PMTR1015 would be recommended) to those terminals before connecting using a good grade of 60/40 electrical type solder (do not use acid flux or acid core solder). Wiring schematic for the more complicated case (for a 4 lane track layout) is shown in this schematic : PDF 


Recommended (Positive Polarity) Wiring

The most appropriate & proper way to wire a 2 lane home track is shown in the following schematic : PDF  This wiring will result in the car moving from right to left as shown. If that direction of travel is not desirable for you, either switch the wires around at the guide shoe of the car or just imagine the track section turned around in your layout so that the bottom is the top & so on, then wire the track section the same, but upside down if you will ... One example of normal "positive" wiring, specific for the Carrera brand terminal track, is shown in the following link : Carrera Wiring


Not Recommended (Negative Polarity) Wiring

Just to cover these bases completely, the following schematic illustrates the "wrong" way to go about this : PDF If curious about the polarity used for wiring of an existing track, this schematic may help. If the track is wired in this manner, the standard polarity car will still travel right to left as shown, but polarity sensitive electronic controllers such as the Professor Motor unit would not function properly without the installation of the optional polarity switch kit. From my experience I would estimate that about 10% to 15% of the slot tracks world wide are wired this way. A small, but still significant number. What is needed to help this issue of different wiring approaches is a global standards making body such as ISO (International Standards Organization) that helps to commonize standards in more major industries. 


Control Panel Setup 

Commercial tracks are always set up with easy to use color coded hook-ups for the controllers and the color also indicates the lane being used. Club or home tracks can also be hard wired following the schematics we have provided and set up in the same way as the commercial tracks with a control panel for each lane. This allows the home or club racer to take advantage of far more robust volume produced slot car controllers and accessories. One easy way to set all this up is to fabricate a control panel with brass screws providing the attachment points for the alligators and color coding the hookups using plastic washers under the screws cut from colored acrylic plastic using a hole saw or cut from clear acrylic plastic and painted on the back. Normal standards for this would place the hook-ups in a black-white-red sequence left to right. A fairly exotic panel for a club track is shown below with a shift lever to select alternate lanes and entry into the track pits, and a "fuel gage". 


More Schematics 

A very valuable addition to a home layout is the adaptation of individual power supplies for each lane of the track. Home tracks with only one small wall pack type transformer can experience a power surge when one of the cars deslots in the other lanes of the track. The individual transformer per lane system solves that problem. The schematic to do this follows : PDF 


Wiring for Reversing Switches 

One thing that can add to your fun with the nice new layout you just finished is to flip a switch and run the other direction on the track. That can, however, cause a polarity issue to pop up with the electronics in our controllers or other brands of controllers that are polarity sensitive. But, there is a solution to that problem if the switches are wired into the track in the proper spot. The schematic for that follows : Wiring Schematic 


Power Tap System for Long Tracks 

For really large layouts or for commercial tracks it becomes necessary to have more than one point where the system is wired in order to maintain consistent performance all the way around the track. These secondary wiring hookups are called "power taps". For commercial tracks that are braided with continuous braid (no breaks at the track joints) a secondary power tap spacing of 50 - 75 running feet is adequate. For home tracks with plastic track it is a bit more demanding because of the very high number of track joints and the fundamentally higher resistance of steel rail systems over heavy copper braid. Actual performance of course depends on the condition of the track and the potential for corrosion and / or connection problems at the joints. The small current that is used by stock 1/32 cars helps to make the issue not as significant, although high performance motors that can be installed and situations where substantial traction magnets are used make this a potential problem if large layouts (50+ feet) are used. Some brands of track are, of course, much better in this regard because of the use of stainless steel materials and design features of the joints. In general I would suggest a power tap spacing of 25 - 40 feet in a plastic track layout. A sample schematic showing how the power tap(s) should be wired for a six lane track is shown on this link : PDF 

Some observations from this schematic - each lane has the left side of the cars braid wired in common to the "ground" or negative side if the transformer & the brake post of each control panel (controller hookup) is also wired to ground. The opposite side of the track where the power tap connects and the cars are running left to right instead of right to left is in effect wired upside down from the "front" straight. The ground side wire of the power tap can be a single (larger gage) wire than that used to hook up the feed for each specific lane ... for example. if 16 gage wire is used the power tap wire going to each lane, then 12-13 gage should be used for the common ground feed. 

Connections can be made to the secondary power taps in a number of ways : in commercial tracks the copper braid is dropped under the track and wires are soldered directly to the braid or high reliability commercial type connectors are used called bus bars. For home tracks you can add additional terminal tracks and plug in the connections, use terminal tracks disassembled with direct connect to the wiring underneath, or with care you can solder connections directly to the steel rails. Scalextric and others make a multi-lane adapter gizmo that just presses on under the steel rails ... this can give you a good connection if the fit is right, or something similar can be fabricated with brass tubing of the right size with the wires soldered to it pressed underneath the rails. When you think you have the system completely wired, get a continuity tester or multimeter to double check the integrity of the wiring before powering up the system.

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