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· Rich Dumas
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4,570 Posts
The simple solution would seem to be to use a 100 watt variable power resistor, that would be a lot cheaper than a 100 watt rheostat. There is a problem with using any sort of resistor to drop the voltage. The voltage drop across the resistor will vary as the load varies, with two cars starting at the same time the load would be about 6 amps, once the cars get moving but are still accelerating they will use about 1 amp and that will drop to 0.5 amps once the cars hit top speed. In that case the voltage drop across a 1 ohm resistor would be 6, 1 and 0.5 volts. If you can live with the cars being sluggish when starting from a dead stop you could try a 10 ohm resistor, that would drop 5-10 volts at the maximum resistance. I am a little unclear on how the slotless system works and I am too lazy to do any research, but I expect that it works like the AC2 system where the track power is AC, there is a diode in series with each controller, one wired in the opposite direction from the other and matching diodes in the cars. Each car sees a DC voltage that is derived from half of the AC sine wave. Using a system like that you could drop the voltage by putting more diodes in series with the ones that are in series with the controllers. The diodes will drop 0.7 volts each, which will be independant of the load unless the diodes are too small. Another thing that would work well is to plug the power supply into a variable autotransformer, these are calles Variacs or Powerstats in the US. Sadly Variacs are very expensive, but you may be able to locate a cheap one on ebay. Do not be tempted to use a regular light dimmer, some of those would cause the power supply to burn out immediatly.
 

· Rich Dumas
Joined
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4,570 Posts
I would expect that the power supply would have AC out, not DC. I was confused when you said "rectified AC", rectified AC would be DC. If there are no diodes in the cars the system must not work like AC2 does.
 

· Rich Dumas
Joined
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4,570 Posts
With the AC2 system two cars can run on the same lane. Each controller controls the amplitude of half of the AC sine wave and the diode in the car detrmines which controller it will work with. The cars see a very dirty DC voltage. It is really half wave rectification, with full wave rectification the negative half of the sine wave gets flipped to fill in the gaps that you have with half wave rectification.
 
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