Track Power Basics

by Arie Viewer

 

Before you can get maximum performance out of your slot cars you need to be sure you’re getting maximum performance from your track and power supply.  If either of these systems is not performing properly your cars won’t either.

 

Track

No matter what kind of cars you are running or what you are using for a power supply you need to be sure you’re getting consistent power over the entire length of the track on all lanes.  Even if every connection between track sections is clean and tight a plastic sectional track loses a tiny amount of current at each one.  If your layout is long enough the sum of these minute losses can result in a noticeable drop in power as a car moves away from the power tap.  If any of your connections are loose, dirty, or corroded the power loss will be even more serious.  If they get bad enough you can lose power entirely over parts of the layout. 

 

In all plastic sectional track systems some variation on a pin-and-socket arrangement completes the electrical connections between one section and the next.  If some of these connections are not making good, tight contact there can be a significant power loss in places.  Two on the same side of the same lane may cause part of that lane to lose power entirely. Ensuring a tight connection is usually just a matter of slightly bending or squeezing the pieces of metal that make contact to ensure that the “socket” fits tightly enough around the “pin” that the pin actually forces the socket slightly larger, creating what is known as an interference fit.  If you have a Scalextric Sport layout you can find a simple technique for tightening your track’s electrical connections in our article, Scalextric Sport Track: Better Continuity For Better Racing. 

 

Along with making everything tight you need all the contacts to be clean.  It’s a good idea to take your layout apart every six months or so and clean the contacts of any dirt or oxidation that has accumulated.  In especially humid or dusty environments you will want to do it more often.  And, of course, you need to clean the contact rails or strips and clean and adjust your cars’ pickup braid frequently so there is good contact between the cars themselves and the track.  WD-40 or anything similar will do the job.  Be sure to wipe off the surfaces thoroughly after cleaning to remove any residue from your cleaner that might affect tire traction.  Don’t use anything abrasive on the metal parts of your track, as it will eventually wear away the plating that keeps the steel from rusting.  Before using any particular cleaner you may have on hand it’s a good idea to test it on a small area to make sure it won’t attack the plastic part of the track. 

 

You can also improve the electrical contact between track sections by using a dab of electrically conductive grease at each contact point.  This kind of grease conducts electricity because it has microscopic particles of metal in it.  The grease fills in small gaps between the metal parts, increasing the contact area, and also prevents corrosion.  You can find electrically conductive grease at electronic or electrical supply houses, or simply Google “electrically conductive grease” to find on-line sources.  The grease can be somewhat messy, so you probably won’t want to use it if you have to dismantle and store your track between uses or if you have to set it up on a carpet or any other surface you don’t want stained. 

 

Power Supplies

The purpose of your track’s power supply, often referred to as a transformer or a power pack, is to convert 110-volt alternating house current into direct current at the correct voltage for your cars and feed it into the track. 

 

Electric current is measured by voltage and amperage.  Voltage can be compared to the pressure of water flowing through a pipe, and amperage corresponds to the total volume of the water flow.  The electric motors in your slot cars will only draw as much amperage as they can use.  If they are not getting enough amperage you can increase their performance by increasing the available amperage but only until the cars are getting all they need.  After that all the amperage in the national power grid won’t make the cars go any faster, but additional amperage won’t hurt the cars or the track unless a short circuit occurs somewhere.  Increasing voltage by any amount will make the cars go faster—right up to the point where the motor eventually self-destructs.  A moderate increase in voltage, four or five volts, perhaps, typically won’t cause a major decrease in motor life, but beyond that you are running an increasing chance of letting the smoke out. 

 

Most ready-to-run cars and track power systems sold today for home racing run on about 14 to16 volts, and most wall-mount power supplies packed in conventional (non-digital) race sets deliver anywhere from 0.75 to 1.2 amps.   That’s enough to run two box-stock cars around the set layout well enough.  However, as soon as you start to add to the layout or modify the cars for greater performance the output of the OEM wallpack becomes marginal quite rapidly.  That’s because every time you install a hotter motor or a stronger traction magnet or even lower the stock magnet for more downforce you increase the amount of amperage the car needs. 

 

 A quick and easy way to make a useful improvement is to go to a separate original equipment power supply for each lane.  Most track systems are designed to make this a plug-and-play operation.  With separate power each car is getting the full output of one power pack.  Even better, each lane has its own power circuit, so the cars are not fighting each other for the available power and what one car does can’t affect the power to the others.  Even if there still isn’t quite enough power for each car this makes them easier and more consistent to drive.  If you plug the power packs into an outlet strip that has an on-off switch you will have a master track power switch for starting and stopping races.

 

However, with longer layouts or modified cars a stock power supply per lane, by itself, won’t be enough.  If the amount of current available is only just adequate to begin with, the cumulative small losses at each track joint will be enough to make the power insufficient at the far end of the layout, and if there are a few not-so-good connections the loss will really be felt.

 

To help with this problem the track system manufacturers make available what are commonly referred to as booster cables.  These are just sets of wires with connectors on the ends that allow them to be attached easily to some part of the track power strips on the underside of the track.  By using them to connect each strip on the terminal track (the section where the transformers and controllers plug in, often called a power base) or the section next to it to the same strip on the far side of the layout you can provide each lane with an extra power tap partway around the circuit, bypassing all the track joints in between and distributing the current more evenly over the entire length of the track.  Many layout builders use two, three, or more sets of booster cables to create power taps spaced equally around the course. 

 

Installing booster cables is a toolless process, but getting the cables connected to the right places can sometimes be confusing.  A good way to keep the connections straight is to code the power strips with stickers on the bottom of the track. Start at the outermost lane and work inward.  Then code the wires to match, as shown below. Do that at both ends of your power tap and you won’t get the wires mixed up and create a short circuit. 

 

Even with booster cables and one stock power pack per lane you can easily go far enough with motor and magnet upgrades on your cars that you simply need more amperage.  Then it’s time to consider an aftermarket power supply.  In addition to providing the extra amperage you need, many power supplies also let you adjust the voltage.  This comes in really handy if you race both magnet and non-magnet cars.  Non-magnet cars are usually more drivable if you drop the voltage to about 10 volts or so.  Being able to reduce the voltage even more helps out when you have small children who want to race but don’t yet have the skill and coordination to drive cars at full power.  Turning the power down to 6 volts makes things a lot easier for them.  In some cases you can even set the power low enough so a very young child can simply pull the controller trigger all the way back and the car will drive itself around the circuit. 

 

Aftermarket power usually comes in the form of one large power supply for all the lanes of your track, but the power supply will have more than enough amperage for even a 4 or 6-lane track.  You can still run a cable to each lane.  The easiest way to get the cables is to cut them off your stock power supplies.  Be sure to leave a few inches of cable on each power supply so if you ever want to splice the cables back on there will be something to splice to.   Separate and strip a couple inches of wire at the cut end of each cable and crimp on suitable connectors.  Connect all the positive wires to the positive terminal on the power supply and all the negative wires to the negative terminal.  Then plug the cables into your power base(s) and you’re on your way.  Oh, don’t forget to plug the power supply into the wall. (Don’t laugh; people have done exactly that.) If you would prefer to make your own cables you can take your power supply and your power base to any electronics supply store and they will be able to sell you everything you need. 

 

Electric Dreams carries a selection of stock power supplies as well as an excellent aftermarket home track power supply, the Pyramid PS26KX.  The Pyramid delivers 22 amps at 6 to 15 volts, readily adjustable with a dial on the front of the box.  It will easily cover the power requirements of just about any cars you are ever likely to run on a 1/32 or 1/24 scale home track of up to 6 lanes. 

 

Before you upgrade your power supply you should consider what you want to accomplish with your racing and how much money you want to spend.  If your track is just a toy for your kids and you are only going to run box-stock cars on it stock power may be all you need.  If your primary interest in slot car racing is simply to create a group of cars that can be raced competitively at low cost and not to pursue ultimate performance a stock pack per lane may be all it takes.  In fact, some people have used power restrictions to limit the cost and complexity of car modifications by keeping the power just sufficient for stock or mildly modified cars.  Determining what your goals are will keep you from spending more money than you need to on power supplies.  It can also help you prevent an expensive and counterproductive “arms race” among the drivers who compete on your track.

 

Most of what we have said here applies to digital systems as well, but there are a few differences.  The biggest one is that there is no way to provide separate power to each car in a digital system.  In most digital systems the cars and the lane changers are all powered by a single power supply.  The exception is SCX’s digital tracks, on which the lane changers are activated mechanically rather than electrically and don’t require power, though the cars are all still powered from a common source.  The original power supplies in most digital sets are more or less adequate to run three cars and the number of lane changers that come in the set.  As you expand the system to run the full number of cars it can handle and also add more lane changers you will need extra power.  Most digital systems provide in some way for an additional stock power pack to be added, and any of them will accept an aftermarket power supply with the required plug.  However, if you add power to the system and also increase the number of lane changers and the number and performance of your cars to make use of it you will reach the point where you can pull enough current through the system to fry critical parts in the power base.  To help avoid this situation some digital system owners have powered their lane changers separately from the cars.  The various Internet slot car forums are good sources of information on this modification and a vast number of possible digital system upgrades various hobbyists have devised.  Before you try any of them, however, it’s highly advisable to post on the forums and get information on the actual experience of people who have done the mods on their tracks. Needless to say, any modifications you make will void the manufacturer’s warranty.  

 

You may have additional questions about track power issues.  We invite you to e-mail us at support@www.electricdreams.com and we’ll give you all the information and advice you can use.  If we can’t answer your specific question we can refer you to the manufacturer’s technical consultants for a definitive answer. 

 

Power to the people…especially when they’re racing slot cars!