OK, here is how it works and what to do if you have purchased an aftermarket Rectifier with no charge warning light circuit. The two yellow wires enter the Rec/Reg and the AC voltage is converted by a full-wave rectifier. Once rectified this represents the 12v DC system. You can still use a three-phase rectifier; only use two of the power inputs. The Red wire is connected to the alternator winding and does supply an AC voltage but it is a signal wire, not a power wire!
To utilise the charge warning light, connect the blue wire to the red wire using a series '1N 4004' diode, with the blue wire being the positive voltage source. When the engine is stopped, a very low leakage current will flow from the charge warning light, thru the windings and thru the Rec/Reg diodes - it is a very low value but enough to illuminate the warning light. When the motor is started the red wire will emit a voltage. The Red wires AC voltage opposes the 12v DC feed thru the charge warning light and the light goes out! The DC circuit is protected by the 1N4004 diode.

Well, let's not argue about it, and it is good to see that you have come up with a circuit that maintains the charge light using a regulator that has no provision for one.
And incidentally a 2 wire alternator is single phase.

One look at two and three phase Alternator diagrams will produce many variants. Three wire 3 phase alternators are available, for instance. This Ducati Alternator is a 2 phase with centre-tap and yes, it appears the tap can be connected to 12v as this next link shows (wiring diagram from a 750GT at bottom of page). Not sure if I'd want to do it what with melting plastic on a terminal when I have sent it thru the rectifier (same thing). So all told its difficult to know if I'm doing entirely the right thing. However, with only the pink wires to the rectifier, it is charging...
http://willyg.homelinux.net/Alternator/
Having a read of this article it would seem that if the two pinks are rectified and the red goes to 12v then high load charging (ie all lights on) is good but low rpm charging poor. If only the two pink leads are sent to the rectifier and the red wire centre tap disconnected (or used for a charge warning circuit) then low rpm charging is better but high load charging is worse. But no harm done.

the center tab is an exit for the positive halfwave. Being positive it doesn`t have to be rectified just voltage regulated as is shown in Dereks picture. The alternator will work also if the center tab isn`t connected or used for something "different" but that will impact the efficiency (curve) of the alternator meaning it won`t reach its full power output potential. At least this is my understanding.

What seems wrong to me is that in Dereks design the center tab connects to negative. That can`t be right.

Have a look at p. 173-179. It`s for the old Duc 860 GT
http://www.ducatimeccanica.com/860_work ... age173.htm

just noticed you had edited your last post

Hi G.

By connecting the 0 volt line to the centre tap gives effectively a 2 phase alternator. So either end of the "coil" will be 180 Deg apart. So when one end is peaking positive, the other end will be peaking negative. This can then be rectified with only 2 diodes to get what is a full wave rectifier, rather than 4 diodes without the centre tap.

It's all about forward biasing diodes and sine waves.

Cheers.

Nick.

Ok so now I've checked with two multimeters just to be sure and it seems that the stator/alternator/whatever it's called is toast, across the two yellows (mine as light tan actually) it only reads 5.Xv AC. The battery stays at a constant 12v, no change any rpm.

So where to source a new one? The reg/rectifier seems to be a bunch on eBay, might as well just replace that too while I'm at it.

My bike has the red wire going to the (Honda )reg/rect as a phase and it all seems to work ok . I also have a bosch alt with a similar set up on my Guzzi and the manual for that sez that the efficiency of the alt is improved by treating this "center tap "( I don't think that's the correct term in this instance ) as a phase and hooking it up to a 3 ph reg/rect

My personal recommendation is to have it rewound as a single phase Stator by these guys, it will be cheaper and newer than buying a new single phase regulator and he will give you a one year guaranty. Can't beat that with a very large stick Shoot them an email and they can give you a current price and turn around time, they are very helpful and responsive BTW there are many reasons why not to use the 3 wire(two Phase stator)
But I am not looking to start another argument. Suffice it to say the single phase will give you more watts for whatever you need over the 3 wire type



Make sure you ask them to put at least 5 foot lead wires on so you can wire directly to a decent regulator like one from this guy



Did this to my 907 with dual headlights( and all the suggested wiring updates and a few of my own) and have solved my issues permanently


I did the FH020AA regulator but I would suggest you go with one of the more modern SH847 which is a true regulator and not a shunt which will insure a long life for your rebuilt stator

Yeah, so between the kids sports, me doing massive amounts of overtime, my project bike & never ending honey-do list I decided to pass the work off to Seacoast in NH. $50 picked the bike up in CT, transported it to their shop via their sprinter van. They're doing a top to bottom overhaul/refresh. Bike should be tip-top when I get it back in time for spring. (Actually it'll probably be done next week).