How do you wire in a one wire alternator when it's replacing a three wire?

It is very simple, use only the heavy orange wire and the black ground wire. The alternator will trigger its self as soon as you increase throttle from idle and will stay energized until you shut down. Tape the un used wires well the purple will be hot when the key is on.

Phil

I'm in the process of doing the same thing.
I installed it, but the alternator manufacturer told me to connect the purple and orange wires together. WRONG!
While I didn't smoke anything, the engine would not shut down. I turned the key off and it kept running. I tried to turn the battery switch off, but it broke in my hands. I quickly pulled the coil wire.
The aternator was back feeding power through the purple wire supplying power to the system.

That sounds too easy! ;-)