Had twin engine boat volvo diesels rewired them to remove the factory harness. One alternator would no longer 'start'. Had to apply voltage to field before it would charge. Had to do this at every start. Why did one charge by itself but the other wired identically would not 'start' ?
As far as I know the polarization switches on “D+” depending on what the alternator does. It’s “-“ when the engine is not running. The lamp in the dash gets plus from the battery when the ignition is on. Thereby it connects battery “+” and the alternator, which gets exited by a few Watts the lamp needs (that’s why LEDs don’t do the job as a battery-light). When starting the engine and spinning the exited alternator - it does its job: Producing energy for the battery as long and as much as the battery “wants” As soon as the alternator is spinning and exited “D+” becomes positive “+”. The lamp in the dashboard gets “+” on both connectors and goes off. (D+ = During spinning “positive”) Then you should have 12.8-14.5 V also on D+. As far es I know it doesn’t have load on it, but could be used or seen as a voltage meter signal. As soon as the alternator is not excited and or stops working (running,charging) D+ becomes “-“ again and the dash light goes on - right before your next headache. As I don’t have an edc on my tamd31 I don’t know what’s happening to the edc, but it might be some kind of electronical headache too. Please let me know if I’m wrong!!!
Yes, I believe you are correct. After some further research I believe these alternators are auto exciting and there is a set of diodes that allow some DC voltage to feed the D+ terminal and thus to other side of the battery bulb in the control panel. I'm just not sure what exactly happens when the alternator fails and exactly how the D+ terminal then becomes a path to ground for the bulb. It must be internal circuitry inside the alternator.
@Spicy-Tuna that code is for the nuetral light. Either faulty wiring or a bad bulb. You can try erasing the code to see if it's (intermittent) if it comes right back wire or a bulb.
Another helpful video for mechanics and owners 👏
Had twin engine boat volvo diesels rewired them to remove the factory harness. One alternator would no longer 'start'. Had to apply voltage to field before it would charge. Had to do this at every start. Why did one charge by itself but the other wired identically would not 'start' ?
Merci beaucoup ❤❤❤❤❤❤
@@AchikSarih je t'en prie
As far as I know the polarization switches on “D+” depending on what the alternator does.
It’s “-“ when the engine is not running. The lamp in the dash gets plus from the battery when the ignition is on. Thereby it connects battery “+” and the alternator, which gets exited by a few Watts the lamp needs (that’s why LEDs don’t do the job as a battery-light). When starting the engine and spinning the exited alternator - it does its job: Producing energy for the battery as long and as much as the battery “wants”
As soon as the alternator is spinning and exited “D+” becomes positive “+”. The lamp in the dashboard gets “+” on both connectors and goes off.
(D+ = During spinning “positive”)
Then you should have 12.8-14.5 V also on D+.
As far es I know it doesn’t have load on it, but could be used or seen as a voltage meter signal.
As soon as the alternator is not excited and or stops working (running,charging) D+ becomes “-“ again and the dash light goes on - right before your next headache.
As I don’t have an edc on my tamd31 I don’t know what’s happening to the edc, but it might be some kind of electronical headache too.
Please let me know if I’m wrong!!!
Yes, I believe you are correct. After some further research I believe these alternators are auto exciting and there is a set of diodes that allow some DC voltage to feed the D+ terminal and thus to other side of the battery bulb in the control panel.
I'm just not sure what exactly happens when the alternator fails and exactly how the D+ terminal then becomes a path to ground for the bulb. It must be internal circuitry inside the alternator.
Hey Ted, thanks for another great video. The other day my EDC diag was flashing 5.2. I can't find anything on this. You ever seen that?
@Spicy-Tuna that code is for the nuetral light. Either faulty wiring or a bad bulb. You can try erasing the code to see if it's (intermittent) if it comes right back wire or a bulb.