Is Exciter wire needed on Alternator?

[sailorman37]

As per the original Universal wiring diagram, I do not see a wire connected to the exciter terminal on the alternator, but only a purple wire to the sensing terminal. However, as per the Mando alternator wiring diagram, there is a wire on both the exciter terminal and the sensing terminal.

After the engine starts, I have to rev it up a bit to get the alternator to put out a charge. The alternator does put out so obviously the exciter wire is not needed, but would it prevent having to rev up the engine to get the alternator started?

If so, what voltage needs to be put to the exciter terminal? I've read somewhere 2 - 3 volts and then others say 12 volts. thoughts on this?

 

[exoduse35]

Run the exciter wire from the "RUN" position of the ignition switch through an idiot light and to the alternator. The EXC. terminal should be grounded when the alternator is not charging and will have battery voltage when it is. This should help get it started but alternators do sometimes need a certain speed to kick on and depending on your pulleys it may just be one of life's inconveniences. The light will tell you if the alternator is putting out, and is off when running because the EXC wire is back feeding power instead of supplying a ground. Edd

 

[Tom Metzger]

The purple wire should come from the key switch run position and go to the exciter terminal. I sounds like someone put it on the wrong terminal. You should check to make sure it does come from that switch, but purple is the correct color for it.

The sense terminal, "S", should be connected to the battery voltage, or just jumper it to the output terminal.

You can Google "Mando alternator wiring" to find documentation of what I am saying.

An idiot light might be nice, but is not required.

 

[sailorman37]

thank all. I did take a look at the Universal and Mando wiring diagrams and it looks as if they used different colors. I believe Universal used purple for sensing and Mando used red/purple. Universal does not show an exciter wire. I may forgo the idiot light since I do have a voltmeter.

Brad

 

[Tom Metzger]

There is an ABYC color code for wiring engines & accessories, E-11 Table XIV: