How do you wire a ford motor 351w alternator when there is only one wire attached and the others are cut? The only wire attached is the large battery one. I need to know what to do with the white wire on the plugin thats been cut and there is the small screw on the alternator that I believe says field that needs a wire.
My answers are general in nature and not for your specific unit.Alternators transfer mechanical energy to electrical using variable reluctance.You need to supply a small field current to set up a magnetic field forthe unit to work. The field is regulated to supply the properoutput current to the battery.What this all means is that the large wire you have attached is to goto the battery and the field wire will go to an externalregulator. That regulator must also be powered from the batteryand so it will have a ground connection( may be through the frame ofthe regulator), a battery connection , and a field connection to thealternator.THe regulators job is to watch the battery voltage so that when thebattery voltage drops , it will supply a field voltage or current tothe alternator. The alternator then takes the field current andamplifies it and supplies a much larger current through the large wireto the battery. When the battery voltage is too high , theregulator will turn off the field and in turn , the alternator willstop supplying the battery current through the large wire.Now , for your unit. Attach the alternator to the motor and startit up. Without field attached, there should be no current to thebattery. You test this by directly measuring the large wirecurrent of indirectly by looking at the battery voltage. Applythe power to the field by either grounding the alternator field OR byattaching it to 12 volys from the battery. One of theseconnections will provide full alternator current and you will see thebattery voltage go high and hear the alternator load down andwhine. Don't hold the field on too long. Now attach thefield to the field connection of the regulator and power theregulator. You should now see the battery voltage slowly run upto 14.0 to 14.5 volts and no higher when it is all workingproperly. Turning lights and fans on in the car will cause thevoltage to drop some but it should not go below 13.8 volts.Other connections from the alternator plug are used to supply the alternator light on the dash board.---Ron