one last alternator/voltage regulator question,..hopefully

[vtrich]

So, I had my Bosch 55 amp. alternator rebuilt by a local shop. It came back with 3 new diodes, new brushes and a new bearing. AND
it looks like new. I have not installed my new Bosch VR yet. I have a new Bosch VR that I have not installed yet. But with the old
Motorola VR I'm getting 12.6 volts at the battery with the car NOT running. When the car is running at idle I'm getting 12.4 or so,...again,
measured at the battery. However, when the engine is revved to 2000 the volts jump to 14.6 and keep moving higher as the revs increase.
This was with the lights on, btw.

So, I need to get my new regulator installed. The old regulator is a Motorola and the wires are attached via circle connectors and spade
connectorsr, but the new one simply has the three spades on the bottom of the housing.

OK,...my question,...the new regulator has a spade to connect the blue wire (D+) and one to connect the Black (DF) and the ground goes on
the last one (D-). However, my current regulator has a heavy red wire attached via a circle fitting. I assume that is from the battery,..but no
place to attach that to my new regulator. What do I do with that red wire. I think it should be attached to the B+ terminal,...but the new one
doesn't have a B+.

I know this is a simple thing,...but evidently way beyond me.

THANKS for any help!!

Rich

[304065]

Rich--

Be careful with electrical things they can kill you or burn the car down.

Sounds like somebody put the wiring harness backwards! Here are the connections. VR only has three connections whether moto or Bosch, D+/61, DF and D-

Hope this helps! A photo of your wires would be best.

[vtrich]

I'll take a pic. when I get home.

I've been pooring over the various threads related to this topic and none of the voltage regulator wiring diagrams I see include a red wire.

So, I'll get a pic. and post later today.

THANKS,

Rich

[304065]

Rich, that will help, over the years harnesses get hacked, it's easy enough to figure it out and get you on the right track once we see what you've got.

[vtrich]

Hopefully these will help. The Blue and red are connected at what I thought was a condenser, maybe
it's a noise suppressor?

But still, not sure about the other red?

THANKS for your help,...once again.

Rich

[vtrich]

Just to be clear, from the first picture. The black wire goes into the round device above and to the
right of regulator and a red wire, coiled, comes out of that device and is attached to the regulator.

Likewise, the blue wire goes into a similar but smaller device below the regulator and exits to the
regulator as a red wire.

The two brown ground wires were connected at the top of the regulator,..that is only thing I
follow comfortably.

THANKS,
Rich

[ESully]

The diagrams never show the noise suppression capacitors. This is the Motorola, the capacitor for the bosch regulator was a little different.
Blue goes to the lower capacitor and then the Red from the capacitor goes to D+/61.
The Black goes to the upper capacitor and the Red lead from the capacitor goes to DF. The Brown ground wires go to the mounting stud.

[304065]

Quite right. Think of the voltage regulator as a great big relay-- when the voltage drops below the set-point, the relay contacts open, and the field current falls, until the voltage being produced in the stator and rectified by the D+/61 diodes ("trio") falls below the set point, at which time the relay contacts close, and the field gets full current again.

It's not like a variable resistor where the strength of the field current is varied-- it's more like pulse width modulation with an on/off switch to get the output voltage where you want it. This is why, when a VR fails, the voltage often goes off the charts, because it's getting the full field.

Anyway, the purpose of the capacitors in this case is to reduce electronic noise-- every time the points open or close, there is a little spark on the points and associated EMF. The capacitor has one leg to the line to the altnernator and the other to the VR-- caps will charge to a DC level and block alternating , so they make good noise filters.

Nice photos Mr. Sully- these should be saved in the Motorola Library along with more. And save that original Motorola VR, they don't make them anymore!

[vtrich]

THANKS to both you guys,...I think I got,...not,...I definitely got it. If the capacitors are
simply for noise suppression and one doesn't really listen to the radio in ones old 911,...
let's just say,...then could one simply get rid of the capacitors,...and just take the blue
directly to D+ and the black to DF?

Thanks again,..you both are a great help!!

Rich

[M_deJong]

Yes you can ditch the noise suppressors with no ill effects. Even more so if you go to a solid state VR. But keep them in a safe place in case the next owner cares!