Mine is generating only 12.3.
I'm unclear what you're meaning or trying to say here - bit confusing.The big wire should go the fuse box first then from the box to the battery. So any voltage drop to the box is compensated. but Alfa ran a short run to the battery. So as the system loads up it overcharges the battery by what ever the voltage drop to the box is.
That is why batterys don't live as long as they should in the alfa.
In the Milano/75 a resistor in the ARC control box is used instead of a lamp.It has to do with where the regulator sence is. in this case the lamp is used as the sence
It's even worse because the cheap [email protected]%$ds only have to run a thin wire back to the battery from the other side of the lamp/resistor as it only has to handle the current through the lamp/resistor.I think this is one of the things auto manufactures do a lot, cut corners.
By not running the thick wire from the box and back they save some cost.
and yes the regulation suffers and battery don't live long but as long as it gets past the warranty period it is not there problem.
Actually, the 'regulation point', or system voltage signal, comes from the most stable point there is; the field diodes output INSIDE the alternator. This output is also alternator terminal D+, the wire that feeds alternator output voltage to one side of the warning lamp. The other wire feed to the lamp, or switched side, comes through the ignition switch and the fusebox. If the voltages from both circuits is the same (zero voltage potential), the lamp is out. If the voltages are not the same, there is a voltage potential at the lamp so the lamp will light. The intensity of the light is proportional to the potential....now if the regulation point was moved to say the stud on the fender it would be a whole lot better as the voltage would be stable there.
so lets say we get 2 volts drop from the stud on the fender to the fuse box. the light will see 11.8V the alt will crank up until it current limits over charging the battery or push the battery to 15.8V (this is why you get the bulge in the battery on a alfa and short battery life) so lets say it made it to 15.8V the voltage at the fuse box is now at 13.8V but a ton of wasted current is going into the battery. if the alt went to the box first then the battery. it would boost the voltage to 13.8V at the box (15.8V at the alt stud) and 13.8V to the battery so no wasted current and no undue stress on the alt or the battery.
now if the regulation point was moved to say the stud on the fender it would be a whole lot better as the voltage would be stable there.
@ slyalfa: thanks for the explanation and example; it makes sense. I presume that a healthy voltage regulator would not allow voltages as high as 15.8V, and your example is just that, to make a point.Voltage drop in the switched circuit has no effect on alternator output voltage.
100% correct. Just to clarify the 'but it's own output' part though means the alternator output, NOT the regulator output. The regulator does not output anything; it simply completes the field winding circuit by varying circuit resistance to ground.I have always presumed the voltage regulator - inbuilt into the alternator - does not rely on feedback from anywhere but it's own output. As such, the voltage at the stud or ARC is irrelevant to the voltage regulator.
It is both an input and an output.What is the 'light green' wire, which is connected to the alternator? I have presumed it is an output from the alternator, perhaps to ARC; but is it an input to help feed back to the voltage regulator?
The field diodes output inside the alternator (which is also alternator terminal D+).The bottom line being: where is the voltage regulator sensor?
As previously mentioned, with KOEO, the voltage on the D+ terminal, having come through the indicator lamp and green wire, also provides for field winding excitation. This allows the alternator to start outputting at a low RPM.
Ah, of course, go it - thanks: ignition power generates the magnetic field in the rotor windings.slyalfa said:It is also used to trickle start the field magnet.
Yes, but ONLY on initial start up. Field power then comes from the field diodes (D+) once the alternator starts outputting....ignition power generates the magnetic field in the rotor windings.