AE86 16V - Alternator Wiring Basics...
Posted: Sun May 04, 2014 9:37 pm
Here is a Toyota schematic of the AE86 alternator wiring...
The alternator has four wires labelled S, L, IG and B.
S is the "Sense" wire that tells the regulator battery voltage, so that
it can adjust the charging rate. Flat battery - high rate, full battery = low rate.
L is for the charge indicator light. When the alternator is charging, the
voltage on this wire cancels the charge warning light.
IG is a switched supply from the battery to provide the initial kick (excitation)
to make sure that the alternator starts generating when the engine starts.
B is the battery wire. This is the heavy wire that connects the alternator to
the battery, and carries the full charging current.
Here are the terminal identifications for the round plug...
So what happens when you connect the battery backwards ?
Well, the alternator is connected directly to the battery positive at all times,
and the rectifier diodes prevent any current flowing back thru the alternator to
ground. When you connect the battery in reverse, battery voltage is applied to
the alternator in the reverse direction, and the diodes (being one-way devices)
cannot block the flow.
Thus, a high current short circuit occurs thru the alternator. If you are lucky
the fusible link will blow before the alternator is destroyed
Cheers... jondee86
The alternator has four wires labelled S, L, IG and B.
S is the "Sense" wire that tells the regulator battery voltage, so that
it can adjust the charging rate. Flat battery - high rate, full battery = low rate.
L is for the charge indicator light. When the alternator is charging, the
voltage on this wire cancels the charge warning light.
IG is a switched supply from the battery to provide the initial kick (excitation)
to make sure that the alternator starts generating when the engine starts.
B is the battery wire. This is the heavy wire that connects the alternator to
the battery, and carries the full charging current.
Here are the terminal identifications for the round plug...
So what happens when you connect the battery backwards ?
Well, the alternator is connected directly to the battery positive at all times,
and the rectifier diodes prevent any current flowing back thru the alternator to
ground. When you connect the battery in reverse, battery voltage is applied to
the alternator in the reverse direction, and the diodes (being one-way devices)
cannot block the flow.
Thus, a high current short circuit occurs thru the alternator. If you are lucky
the fusible link will blow before the alternator is destroyed
Cheers... jondee86