Anyone ever set RPM with stator voltage

[Rhoderman]

So, you're taking the manual statement that 3600 RPM is 28V. And saying that 0 RPM must be 0 Volts to create two points on a line.

I've always said (jokingly) that "If a linear fit is desired, only take two data points." However, in real life, it simply doesn't work that way. In your case, there will be a threshold RPM where it will begin to start generating current. This will be AC voltage upstream of the rectifier, converted to DC by the rectifier, and regulated by the regulator at about 14 to 15 volts to charge the battery.

I still don't get the 60 Hz part. I'm an EE, so I know a little about frequencies and things like that. But any stator I've seen has multiple coils. Try looking here for more information: http://www.simpletractors.com/servic..._electrics.htm (I apologize to the mods if linking to that site is undesirable).

In that link, I see they say "28VAC or more". I wonder if the "or more" part is throwing you. Each one is bound to be a bit different. Also, this voltage will likely vary with load. If you just started the tractor, the load will be higher since it is trying to recharge the battery. Turn on the lights, or run something electric and it will probably change too.

I suppose you could use a tach and measure the voltage at different RPMs for your particular machine, and create a table. Wouldn't it be easier to just use the tach though?

Since I only have one tach, and it's permanently mounted on a different tractor, I'll probably use my Fluke 187 DMM and measure HZ on the coil wire that attaches to the points. I'll multiply that value by 2 and have RPMs. I haven't done this yet, so no guarantees, but I think it will work.

I hope some of this helps you out a bit. Good to see you're thinking "out of the box" though.