Alternator wiring HELP

[x7734x]

OK I have searched hell and high water for a diagram for a wire a 3 wire alternator. I need to know if this is correct and does anyone know if hooking it up reversed will fry it? I have tried both of the alternators I have and both of them are not charging. I'm only getting the same ammout of voltage that is going in from the output on the alternator (around 12) when the boat is running.
Black from the alernator goes to the "switched" wire in the boat. This is the excite wire and has the diode in the plastic casing so it reverses the voltage once its started.
Red from the alternator goes to the 12v constant in the boat
Orange is the charge wire.
Thanks in advance.

[BrendellaJet]

Is this a delco unit? If so I found an old post by Oldsquirt when I was having a problem wiring my alternator(3 wire delco), I copied it to paste here:
"This is how I have always had my Delco alternator wired. Same setup, two different boats, 20 years. Look at the alternator from behind and with the connector facing straight up. The existing wire from ignition switch goes to the right hand terminal. You need to run a separate wire from the left hand terminal to the output terminal of the alternator."
After that run the output terminal to the + terminal on the battery.
As far as frying it. When I was toruble shooting mine I had it wrong a couple of times. I only ran it long enough to realize that it wasn't showing a charge though...

[DelawareDave]

If the terminals are marked with 1 and 2, #2 goes directly to the output wire on the back of the alternator. I just put a crimp on end on mine, and attached it. #1 goes to a switched power source that comes on with the key. This is also the wire where you would put the diode, allowing current towards the alternator. The post on the back, that may or may not have a red insulator, goes directly to the starter solenoid, the same place where the positive battery cable goes.
If the alternator terminals are not marked, from the back of the alternator, #1 is the right, and #2 is the left.

[Moneypitt]

I think there is a little misconception about the purpose of the diode trio...A 3 wire GM integral is a wanna be one wire, just run a wire from the R/S to the output term. This makes the output wire the exciter.....works......No need for 12V from the key.......Maybe someone else can explain the diode's purpose better, but I think it acts as a one way, output only, switch. The battery voltage can't feed back thru the diode and drain the battery. Hense, bad diode trio, dead battery overnight............MP

[DelawareDave]

The way I understand the reason for the diode in the exciter circuit, is to prevent power from the alternator going back to the ignition, after the key is turned off, and causing the engine to continue to run.
The diode bridge that is built in is to convert the normal alternator's A/C output to D/C, as is required by the vehicle's electrical system. It also acts as a one-way "check valve", only allowing electron flow towards the battery.

[Jetaholic]

The way I understand the reason for the diode in the exciter circuit, is to prevent power from the alternator going back to the ignition, after the key is turned off, and causing the engine to continue to run.
The diode bridge that is built in is to convert the normal alternator's A/C output to D/C, as is required by the vehicle's electrical system. It also acts as a one-way "check valve", only allowing electron flow towards the battery.
Actually...
The rectifier in the alternator converts the 3 phase AC output from the stator winding to DC. There's also a small filter capacitor in there to help filter out the ripple. The output of the rectifier is fed straight to the charge post.
The internal diode trio (the reason for a "trio" of diodes...one for each phase) supplies DC power to the voltage regulator circuit. The voltage regulator circuit is the power supply to the field coil. Instead of using a permanent magnet as the rotating magnetic field, they use a field coil. By varying the voltage to the field coil, this makes it a variable magnet and raises and lowers the magnetic field intensity of the field coil, which in turn raises and lowers the voltage output of the stator coil.
The excite terminal on the regulator has to have voltage on it to "wake up" the alternator so that the regulator will supply power to the field coil. No power to the field coil, no spinning magnetic field within the stator coil, which means no induced voltage in the stator, and therefore no alternator output.
Moneypitt is right. On Delcotron alternators, a very common mod is to run a jumper from the excite terminal straight to the charge post. This essentially makes the 3 wire alternator a 1 wire alternator.
As far as diodes go, you can place a diode inline with the charge output to the battery if it's rated to handle the amperage output of the alternator. The anode would come off of the charge post of the alternator while the cathode would go to the + terminal of the battery. This way the battery can't backfeed its charge through the alternator while the motor is off.

[x7734x]

I tested the black wire on the alternator that has the diode in the plastic casing that plugs into the alternator. The diode lets voltage through for a split second then it reverses and sends it out the other way. I found this out through trial and error. Thanks for the input and hopefully today I can get the dam thing fixed.