A 16D motor has a 0.7 ohm armature, at 12 volts it could pull over 10 amps when it first starts up. Free running at 12 volts they pull about 1.2 amps. I have never measured what they will pull when a car is going around the track, but 5 amps per lane should be enough. A "home set" 16D motor would use less power.
Thanks For the info. What I am trying to do is install a small power supply into my slot car box to break in motor's and to power my Hudy tire machine. I already have a 110 volt system with two 4mm plugs to power my iron and light I left a feed for some type of transformer I wired a DC meter from 0 to 20 amps a switch and a wired reastate to adjuct the amps. Thanks Mike
A Hudy is powered by an R/C motor, free running they pull 1 amp, how much they will pull when you are truing a tire depends on how much pressure you apply. I power my Hudy with a Pyramid PS-26KX, which has volt and amp meters. I true at 10 volts and keep the amps between 2 and 3. At that power level it would be best if your power supply had fan cooling.
I use an old telephone transformer, .75 amp's for that, works great. Just put two alligator clamps in place of the plug...
You can find them from .25 to 2 amps cheap, don't toss that old transformer from used up DC stuff. Those little black boxes can come in handy.
I use a DC regulated Power supply that has meters for volts and amps. There a three settings for voltage ranges, which works great because you can dial in specific voltage in each range, and see what the cars draw as far as amperage. It's also good if you have first time racers, you can increase voltage as they get used to the track.
What about a laptop power supply? there are some cheap ones on ebay that can switch between 5 or 6 voltage levels and put out about 5 amps. Plus they are nice and compact so they won't take up too much room in your pit box.
It's all going to depend on what kind of tires you are truing also. Maybe the smaller 1/32 scale stuff would be an amp to two amps. I have a 12V-8Amp Wrightway portable power supply that I use on my 1/24th scale cars because truing those tires, the amp draw is about 3 amps. When I cut down donuts, it's closer to 5 amps, so it's going to depend on the tire and/or the motor. If you are making one, give yourself at least 50% headroom on the amperage, just to be safe, and when you are done, make sure to check for any AC ripple.
Some work straight away, some can be made to work, some cannot.
A common problem is they turn off on low load. This can be overcome by putting a resistor permanently across the output. Some need quite a few watts of load, so getting rid of the extra heat is an issue.
At worst they just won't work on motors, possibly because the protection circuits don't like the motor's commutator switching spikes.
Make sure you get one in a proper case with all the high voltages enclosed.
Worth a try if you've got one for free (like out of a scrap PC), may not be a good idea if you are buying one at full price.
Last edited by Al's slotracing; 04-13-2011 at 01:00 AM.