Alternator wiring

If you should happen to get the wires reversed, the meter would show + with the engine not running and then show - with the system working. If the happens, just switch the wires on the amp meter.

A quick way to check if the alternator is charging is to hold a wrench against the rear bearing of the alternator. If the alternator is charging then the wrench will be attracted to the shaft due to magnetism. If there is no attraction, the system isn't working.

I installed a Delco 10SI, three wire, internally regulated alternator on my Oliver 77 diesel a couple of years ago. I don't have a diagram but I will explain how I wired it up. It works great.

1. Run a wire of 10 gage or larger directly from the main output stud to one side of your ammeter. If you are changing system polarity, you may have to switch the leads on your ammeter. It will be obvious. It you show a discharge after starting, you need to switch the leads around from their original positions.

2. Get a NAPA EHCHLIN #V148 pigtail connector to mate with the two spade terminals on the alternator. You don't HAVE to have this connector but it makes installation easier.

3. Connect the red wire from the pigtail (spade terminal #2 as marked on the alt housing) directly to the main output stud. That is the regulator connection.

4. The white wire from the pigtail (spade terminal #1 as marked on the alt housing) is the exciter lead. It needs to be connected to battery positive through a switched circuit. My starter is foot operated so I don't have a starter switch. I used a normally open switch actuated by oil pressure to complete the exciter circuit. NAPA BALKAMP #701-1575 is a normally open switch that actuates at a pressure of about 4 psig. I installed it where it will see main oil pressure upon engine starting. I wired one terminal of this switch to the alternator white pigtail. The other terminal of this switch is wired to the battery positive post.

This has worked fine for me.

Rod

It will not work with Nippondenso or Mitsubishi alternators however.

On my 770 I used 3 diodes from Radio Shack and wired them in parrallel in order to have enough current capability in the exciter wire. These only cost about $2 and work like a charm.