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What is a Self Exciting One-wire Alternator?
A self exciting or "One wire" alternator as it some times called, has only one wire running to it., that one wire is the main large battery wire. Don't confuse one wire because the plug going to the alternator only has one wire to it, this is a two wire system. The one wire, self exciting alternator that uses a special voltage regulator that doesn't need an ignition wire to activate it.
This type alternator only requires a battery wire hooked to it. The voltage regulator contains
circuitry that uses the residual magnetism in the alternators fields to determine when
to turn the alternator on, the regulator does this by sensing the RPM the alternator is turning.
When the alternator gets to a certain rpm the voltage regulator "turns on". Typically you start
the vehicle, rev the motor slightly then the alternator starts charging. This type alternator is
commonly used on custom cars & trucks, tractors and other non standard applications when
wiring is a factor. In choosing this type alternator you must consider, do you want
to rev your motor slightly to get the alternator to turn on. Also when using the self-exciting
alternator on tractors or other slow turning motors does the engine
have enough RPM's to start the alternator charging. This can be overcome by using a smaller
pulley or by adding an ignition wire. Is another name for the Self-Exciting Alternator mentioned above. You only need connect the battery wire (one-wire).
Two-wire Alternator:
Most standard and all self-exciting regulator alternators will work using the two wire setup. Two wire means that you use the battery wire and an ignition wire to activate the alternator. With this setup the alternator starts charging as soon as the engine is running
Three-wire Alternator:
This setup uses a battery wire, ignition/warning light wire and voltage sensing wire, Three wires.
