Hi guys, I bought a Bosch alternator from Supercheap (BXD1242a) a few years ago but never fitted it. Now I've come to chuck it in my 73 240z and the wiring is a little different.
There are the obvious earth points and the BAT or B+ terminals but the old alternator had a 'T' shaped terminal with 2 connectors, L(amp) & S(ense). The new alternator only has one terminal called D+. I think I can disregard the S connection (leave it unconnected) and then hook up the L connection to the new D+, can anyone confirm?
Originally the car had an external alternator, I replaced this with an internally regulated unit using the plug with a diode in it (http://www.thezstore.com/page/TZS/PROD/12-4068).
Notes taken from http://www.zhome.com/ZCMnL/tech/280Alt.html
1. An "L" connection which goes to a "switched" 12V supply. By this I mean a 12V source that is active only when the ignition switch is in the ON position. I use the mnemonic "L" for "lamp", the alternator warning lamp (if used) is in series with this connection. This terminal also supplies the "excitation" current to the alternator field winding at engine turn on, allowing the alternator to begin producing voltage as the engine is ramping up to idle speed. Once the alternator rotor is turning fast enough, it generates it's own supply for the field winding and the current in the "L" connection stops flowing. The warning lamp (if used) goes out.
2. An "S" connection which goes as close to the positive terminal of the battery as physically possible. The "S" connection "senses" the battery voltage and this is the voltage that the regulator is tying to control. This connection has a high impedance, so it only draws only micro amps from the battery, so it can be left connected without fear of battery discharging.
"S"
...............
: ------- :
:.... | ....:
: | :
: | : "L"
:.....: