Alternator wiring

[RonON]

Hi everyone,
I am in the process of replacing my generator with an alternator. This requires that the ground be changed from +ve ground to -ve ground. Does the coil wiring remain the same. Currently the keyed ignition switch (not the safety switch) is connected to the -ve post on the coil and the +ve post goes to the distributor. Does this remain the same when I install the alternator or does it need to be switched? The alternator has 2 wires, one going to the battery via an ammeter and the other going to the warning light. If anyone has a wiring diagram for this hook up I'd appreciate it. Thanks, Ron

 

[Steve@Advance]

Yes, the coil primary wires need to be reversed. The wire from the ignition goes to the + stud, the wire to the distributor goes to the - stud.

Are you changing from 6v to 12v? If so, you will need a 1.5 ohm resistor ahead of the coil, or buy a true 12v coil.

The wires on the amp meter will need to be reversed.

Assuming you are using a Delco 10SI 3 wire alternator. Easy way to connect to the amp meter, splice into the disconnected BAT wire removed from the regulator.

If you don't already have it, get the harness plug that goes in the side of the alternator. The red pigtail goes from terminal #2 and doubles under the BAT post. The white wire from #1 goes through the indicator light to the ign side of the ignition switch. The harness plug can be bought at about any auto auto supply.

You will also need a wide pulley to match the wide pulleys on the crank and water pump. It can be found at various online locations, speed shops.
Wiring

 

[RonON]

Thanks Steve. So you are suggesting that the keyed ignition switch (not the safety switch) be connected to the +ve post on the coil and the -ve post goes to the distributor. My coil is a 12V coil since my tractor had a 12V electrical system from the date of manufacture (1952). However, as I explained in my initial post, my alternator has 2 wires (not 3 wires), one going to the battery via an ammeter and the other going to the warning light. Do you have a wiring diagram for this type of alternator. I have a 2-wire plug for the alternator, a bracket, a wide belt with the proper length and a wide pulley for the alternator. My alternator is a 45 amp alternator. Will this work in this application i.e. will it only charge at high revs? Ron

 

[Jim.ME]

(quoted from post at 17:00:15 10/15/20) Thanks Steve. So you are suggesting that the keyed ignition switch (not the safety switch) be connected to the +ve post on the coil and the -ve post goes to the distributor. My coil is a 12V coil since my tractor had a 12V electrical system from the date of manufacture (1952). However, as I explained in my initial post, my alternator has 2 wires (not 3 wires), one going to the battery via an ammeter and the other going to the warning light. Do you have a wiring diagram for this type of alternator. I have a 2-wire plug for the alternator, a bracket, a wide belt with the proper length and a wide pulley for the alternator. My alternator is a 45 amp alternator. Will this work in this application i.e. will it only charge at high revs? Ron

It would help to know what brand your alternator is. How about posting a couple pictures of it showing the entire alternator and the wires terminals on it.

 

[Steve@Advance]

Does your alt look like this one? If not, look for a brand name or send a picture, or find one like it and copy paste it.

If so there is another terminal beside the one connected to the light. It simply loops back to the BAT stud, over the wire going to the amp meter.

#1 to the light, #2 to the BAT stud, BAT stud to amp meter.

It may need to be revved up to initiate the charge, but will continue to charge at lower RPM once it begins charging. It will need to be revved each time the engine is started.
10SI Delco

 

[RonON]

Yes Steve it looks similar to the one in the pic that you sent. I don't know the make off the top of my head and will check later. Do you have a wiring diagram for this type of alternator? Ron

 

[RonON]

Steve & Jim, Here are 2 pics of the rear of the alternator. I can't find a manufacturer name anywhere but it says "Made In USA" on the back. The pics show the 2 wire plug with the red wire going to the battery via an ammeter and the white wire going to the indicator light. Does this help with a wiring diagram? Ron

 

[RonON]

Pics won't upload so I'll try with another post labelled "TEA20 alternator wiring"

 

[RonON]

Here are the 2 pictures that i tried to post earlier. Does this help with a wiring diagram for this 2-wire alternator?

 

[RonON]

Got them uploaded here so won't do another post. Sorry about all of the confusion! Ron

 

[Jim.ME]

That is a 3 wire Delco 10SI type alternator.

Battery terminal should have a heavy (10 gauge) wire from the ammeter, solenoid or other major 12 volt source connected to the battery.

The T1 terminal is the switched wire that energizes the alternator to start it charging. If the source is the ignition switch it needs a 50 volt, 1 amp diode, a 10 ohm, 2 watt resistor, or an incandescent indicator lamp (must have two lead without a grounded base so it can be wired in series) in the wire between the switch and alternator. Without a resistor, diode, or indicator light in the wire, the alternator will back feed the ignition and it won't shut off when the key is turned off. An oil pressure switch can be used instead of the ignition switch, but it must not be powered from the ignition terminal of the ignition switch.

The T2 terminal is the voltage sensing terminal. It is used by internal regulator to determine the status of the system's charge.
Common sources of power for this wire are: the battery terminal of the alternator, the battery terminal of the solenoid, or an ammeter terminal.