Greg, ok, I got it straight between yours and Jim's alternators.
He is external rectified and yours is internal.
I understand that your alternator works fine on a test bench but not on tractor. Am I right here?
If your wiring diagram is correct, then there should be no reason an alt with a perm mag field should not work at max chg with the voltage reg disconnected. The regulator, in your case can ONLY limit the amount of charge but can not prevent charging because it has no control over your alternators magnetic field strength as is done in conventional alternators.
It possible, but not likely, in your case that the VR is taking the alt output and bleeding all of it off to gnd. This is why you want to disconnect it when checking your alt for output so that it is not a player.
1. Does your tractor have a charge indicator lamp? If it does it needs to have a lamp controller switch. All systems with indicator lamps must have a switching circuit of some kind to turn lamp on and off. This switch is usually built into VR. Your wiring diagram shows no indicator lamp circuit and that has got me wondering. The wire that you show coming from the VR (R) and going to the battery would most likely be the one going to the charge indicator lamp. This wire would be used to put B+ on the back side of lamp thus turning it off when alt charges.
The B+ for the front side of lamp would come from ignition switch. In other words lamp would be in series between ignition switch and the VR (controller) unit. The VR provides the gnd for lamp when key is turned on, the VR then replaces the gnd with B+ when alt charges thus turning lamp off.
2. With VR? disconnected do you show 14/15 volts DC at alt terminal (R) that goes to battery? If answer is "Yes" then does the same or close voltage show at battery B+ terminal?
If answer is Yes to voltage at alt but NO to voltage at battery then there is an open or very high resistance between the two points.
3. The AC tap (Y) coming out of your alternator is most often used to control a charge indicator lamp or run a tachometer on diesel engines not using a mechanical tach.
4. On Jim's unit (5amps) there is no need to control the charge amps since this rate, minus constant fuel solenoid draw, is like leaving battery on a trickle charger.
5. One last point, using an analog dc volt meter (needle type) on an AC circuit will only show half of the AC voltage present (pos side of sine wave) . You can double this number to get a rough idea of the full cycle peak to peak AC voltage present in stator. You must hook meter from one of the two AC taps on your alt to vehicle gnd. Do NOT hook DC analog meter across the two AC taps because the negative half of the AC wave will try to force needle down below zero and you may never see it again.
cheers,
