Hi, folks, I just registered today, my first post here. Does anybody know a good trick for reducing the top speed of HO DC motors? I've got two ROCO / ER Sharks which run a bit fast for my liking. I removed all the circuit board stuff from the top of the motor ( I do this on most of my locos, so I can wire them in my own style and make room for more weight, etc... ) I do not use DCC, strictly analog. I've tried using resistors, but haven't hit on the right solution yet, they usually overheat. Changing the gearing seems like a very difficult solution to a simple problem. Thanks in advance.
Diodes in series with the motor will each drop .7 volts and don't get as hot as a resistor. You have to put two of them in parallel with each other, but reverse polarity, for each .7 volts you cut. That way the engine will still go foreward and backwards. So 4 diodes will drop 1.4 volts, 6 diodes 2.1 volts, 8 diodes 2.8 etc.
