by RichD » Tue Apr 29, 2014 7:35 am
The value that I posted was for one car with no traction magnets. The track had a regulated 20 amp power supply set at 10 volts. The power supply had digital amp and volt meters. If you know the resistance of a motor's armature you can calculate the stall current. Even for motors of the Scalextric type that can be higher than you would expect. Once a motor turns over it generates a back EMF and the current draw drops off a lot. The biggest strain on a power supply is when the power first comes on and all of the controllers are punched. If the power supply can't supply enough amps the voltage will sag, even if the power supply is regulated, and the cars's acceleration will be a little sluggish. The period that the voltage will drop is very brief and will not matter much since everyone woud have the same handicap. The exception to that would be a drag strip where you would always want to have full voltage.
On my track fuses only got blown if someome hooked up a controller wrong, that happened often enough that I switched to breakers. If you hunt around you can find breakers for about $5 each. I have seen what can happen if you have no protection at all. I watched a nice custom built HO track burn up because someone hooked up wrong with a car already in his lane. On tracks that had fuses or breakers with too high of a value I have seen even robust controllers like a Parma Turbo burn up. All of the 1/32nd tracks that I race on have XLR connectors, which eliminates the problem of misconnected controllers. I would like to have them on my HO track, but I do not think that anyone would put XLR connectors on their controllers.