I was hoping Wikipedia would have a good article, but it just looks like someone tried to make it as complicated as possible. It's actually pretty simple - the controller is just a very fast on/off switch. It probably even says how fast in the specs. If it is fast enough, it can turn on and off fast enough that the motor can't tell that it is pulsing. However, since it is off a period of time, less power gets to the motor. For example, a 50% duty cycle means it is on only half the time, so the motor runs (roughly) at half power. So you can't measure the voltage output - the voltmeter can't read fast enough. Now, at 100% duty cycle, you should be able to read the voltage since it is permanently switched on at that point. That also means that it shouldn't be any slower than running no controller at all when asking for full power. The potentiometer itself should not be handling any real power (a huge flaw in the OE design), and it is probably expected to just make a 0-5v signal to the controller at nearly no current.
Sent from AutoGuide.com Free App
"Lots Of Trouble; Usually Serious"