another alternator question

[vtrich]

THANKS to you both. My Bosch externally regulated alternator will be completed early next week, so I'm simply going to reinstall. After reading
many posts by John and Lorenfb about heat and electrical components, I've been having second thoughts about the whole internal regulator thing.

The wiring on the back of my alternator had the ground strap connected to the cast housing and as you guys have pointed out in the past, there
is probably more resistance at that point. My housing had been powder coated at some point as well and I'm sure the ground was not as good
as it should have been. So, I'm planning on finding a longer ground strap so I can connect the engine case to the D- post on the back of my
alternator. I assume that would be preferable?

I only had 3 connections on the back of my alternator, DF which included an "L" shaped spade fitting with two separate wires,..one in each
of the two spades,...the red to B+ and the Blue to D+. Nothing connected to D-. That sounds consistent with what I'm reading.

THANKS so much for the feedback!!

Rich

[304065]

Rich. . . look VERY closely do you see that D- is the horizontal pin?

[vtrich]

EXCELLENT! You da man!! That looks exactly like mine.

I could see that the DF wire is bundled with a brown ground and they, combined, plug into the tabs, just like in your picture.

I get thrown off track because I see pictures of some alternators, presumably from the same vintage as mine, but with just
one tab (DF), so in that case I guess those alternators would have a separate threaded stud as the D-.

As I said, I was hoping to run the woven ground cable from the engine to the D- on my alternator,...but I guess I will just
clean the housing really well and make sure the connection is really clean.

You've probably already figured this out, what else could lead to such dense questions, but I'm a banker by trade, so there is
a reasonable explanation.

THANKS again I can't tell you how helpful this is.

Rich

[304065]

Yep, like this:



Just make sure you have a good metal-to-metal contact between the alternator case, the fan housing, the spot where the ground strap bolts to both engine and alternator, and you should be OK.

[M_deJong]

Sorry I checked out for a while. In photo above Motorola/Marchal on left, presume Bosch on right.

Motorola is missing its isolation diode bridge.

[Mauireman]

With the engine running you want to see about 13.8V, at around 1500rpm or higher.
When the key is turned on, engine not running, you should read battery voltage to ground on the R/Bk wire, blue D+/61 wire and the black DF wire. If no reading on the R/BK problem at ignition switch, it is not fused. If no reading on the blue wire, lamp is burned out or internal connection from lamp holder to R/Bk is bad. If no reading on black wire to ground the contact is open in the regulator. Bad regulator. Without power on the black wire then the alternator cannot produce power. If the voltage is too high then the contacts are staying closed too much. The battery power on the red wire will not pass through the alternator because the diodes do not allow it to travel in that direction.

Basics. Key is turned on, Power from ignition switch to R/Bk feeds gages. Indicator lamp is tied to R/Bk inside gage, power goes through 2 watt indicator bulb to blue wire feeding D+ on regulator. Since alternator is not spinning to produce voltage, lamp lights up due to voltage difference. Power flows through regulator out to DF to Alternator DF. Power energizes (excites) field in Alternator which creates magnetic field.
Alternator spins, rotating magnetic causes AC power to be produced in stationary coils, and the diodes which only allow current to flow in one direction convert it to DC. Voltage is now provided to B+ and D+. Regulator is set to open contacts when voltage exceeds set point to stop power, closes when voltage drops. Output of D+ is now equal to Voltage on R/Bk so there is no longer a voltage difference causing lamp to go out.
Attachment 252251

Do you have a recommendation for an after market external voltage regulator for the Bosch alternator?

[304065]

https://www.amazon.com/REGULATOR-BOS...tage+regulator