Charging..... but not 100%

I was trying to look up how to hook up a 3 wire to the alternator but i have a Mag and im not sure how to do it, i did try to wire it up with out the use of a switch i just went right to the amp meter but that does not seem to work. Iv also noticed that i can get it to charge by just touching one of the terminals on the amp meter to a ground and that will make it charge right up. could i have a bad meter? or a bad ground on the meter? or do i have to make a ground from the meter to the ground? i have clean terminals and connections brand new battery. Im a little lost here, i have never had a problem like before.

Thanks again!!

Andrew

CAREFUL, before you "let all the smoke out!

Check out Bob Melville's most excellent diagrams at his site linked below.
BobMs place

I wired it up to the 3 wire method that Bob M uses but my M is still on the Mag and not distributor so i do not think that it is getting excited or something to that extent? where should i run that terminal 1 wire to to the amp meter or the battery + side? I also recall that when i got the alternator it had a plug over those 2 terminals if that has anything to do with that?

Andrew

The diagram suggested below is great.
You can put a on with pressure switch in the oil gallery to give the exciting terminal voltage.
They have two terminals on them, one to the load side of the amp meter, and the other to the alternator. JimN

Andrew – First off, never, never, NEVER, ground either ammeter post! You can ruin the ammeter, set the wiring harness on fire, and if the engine is running even burn out the alternator by grounding the ammeter!

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To your other problem: You need to wire up some sort of switch to manually or automatically excite the alternator at startup. There are several options to accomplish this:

1 – Install a oil pressure switch with normally open contacts (ie. contacts that CLOSE on sensing oil pressure) on the engine. Wire this switch between a constant 12 volt source and the ammter #1 terminal. The pressure switch will “turn on” the alternator when it senses oil pressure, then break the circuit when the engine stops.

2 – Install a momentary pushbutton switch in place of the above. After starting the engine, push the button briefly to “flash” the alternator and cause it to start it charging. (So long as it remains spinning the alternator will continue to charge after you release the button.)

3 – Replace the tractor’s existing magneto kill (ignition) switch with a DPDT toggle switch. Wire one pole of this switch to ground the magneto with the switch “off”. Wire the other pole to supply 12 volts to the alternator #1 when the switch “on”.

Hope this makes sense!

Andrew, a little logical thinking will get you out of this...

The only reason the distributor makes any difference is because the ignition switch is then used to perform double duty as the alternator excitation switch.

You can't do that with a magneto switch because it works differently. It grounds out the magneto, whereas the distributor ignition switch connects the battery to the coil.

Sooooo, you need some way to get excitation current to the alternator. On a distributor tractor, that's done with a switch, and you don't have a switch. You need to add a switch.

Run a wire from the + on the battery, to a new push-pull switch that you mount somewhere on the platform (maybe an old ignition switch or reproduction so it looks like it should be there), then to a diode or LED, then to the alternator.

First off thanks for everyones help here, i realllly appreciate it! I got it to charge by hooking the exciter wire to the battery to excite it. However.... it charges 17 volts!!!.... I think i need to hook up a external regulator to it? Im going to have to wire up a switch so that i will be able to kill the power to the alternator and not drain the battery.

Thanks Veryyy much again!!

Andrew

<img src = "http://ndtc3500.stellarnet.com/~blweltin/Bob/AlternatorHarness4.jpg">

Look CAREFULLY at your alternator. Does it closely resemble the internally-regulated 10SI unit above, especially in the area of the 2-terminal electrical connector, with the terminals pointing outward, and arranged like THIS... - - ?

The drawing below is of a 10DN alternator that NEEDS an external regulator.

Notice the different location and type of electrical connector?

<img src = "http://ndtc3500.stellarnet.com/~blweltin/Bob/Delco10DN.JPG">

Which one do you have?


NOTE... there is a relatively RARE version of the alternator in the upper photo that DOES NOT have an internal regulator. It's terminals are arranged like THIS... .

Thanks Bob, i have the bottom one. I was over a freinds house last night and he gave me a mitsubitshi alternator i put that on it and it chaged 15.2 volts is that too much to? if it is what reglator should i by and is there a chart on how to wire one of them up?

Thanks for walking me though this!

Andrew

I think I would check your meter on a known to be good charged 12v battery it should be 12.6 to 12.7 volts. if more, it is your meter. Certified meters are more than 100$ if yours is close, use it, if wrong, factor in the error. all the time! JimN

Jim i was useing a good fluke multi meter. so i think that the volts are correct, i posted a new thread about what i have done on the "first page". Thnak you very much for you help as all ways! really appreacate it!!

Andrew