Anyone Running A Mechanical Voltage Regulator 67 Dart 273 2bbl

[Mattax]

What's the right way?

It's been years but I wouldn't be surprised if I screwed this up.

It really doesn't make any difference performancewise.
Both approaches are used nowadays.

With an alternator that has one permanently grounded brush, a regulator that controls feed must be used.

Alternator with both brushes insulated were originally used with ground controlling regulators.

But they can be used with (+) controlling regulators by grounding the second brush to the case.

Something Redfish mentioned which I believe is a valid concern. The rotors in some of the higher output alternators draw more current. This may kill regulator components not built for those loads.

1973 Dodge Chassis Manual 'Squareback' alternator

Field draw is a little higher.

And this was posted on a Ramcharger truck forum. Prob late 70s 'Revised Squareback' Alternator

It's my impression that the Mopar Performance electronic regulator, Standard's VR 128, Napa VR 1001 have a higher failure rate when used with a higher draw rotor - especially a revised squareback. IIRC that regulator cross references to Studebaker applications - probably its original use - and probably went with a relatively low current draw rotor.

One nice thing about a mechanical regulator; its easy open and to see how it failed.

 

[RedFish]

What's the right way?

It's been years but I wouldn't be surprised if I screwed this up.

I used the harness connector for later model solid state regulator. I added a screw hole and a small spacer to mount that regulator about where my original mechanical regulator was. The little black harness connector cut off the green wire at regulator was reused on the alternator end of my added blue wire. I lifted the engine harness to put the new added wire under tape like OEM.
I wish I had known a new insulated harness connector for my oil sender was available at that time. Source for that showed up in a thread here a couple months ago.

 

[KitCarlson]

Mattax posted this excellent electro-mechanical drawing of early voltage regulator.

Electrically it looks like this:

It is a basic normally closed relay circuit. As IGN voltage increases, the relay coil energizes magnetic circuit show with hash marks, contact pole swings to lower grounded contact. The resistors in the circuit serve as snubbers, giving the inductive current a place to go, reducing contact arcing. Inductors store current, the connection to ground actually conserves the current. In an electronic regulator, a diode provides the path, often called freewheel diode. The diode serves as an automatic valve eliminating need for contacts, cheap too. In this early block diagram of electronic regulator the diode is in a block called suppresor.

I think they were hiding the detail of diode as trade secret.
The zener diode provides the voltage reference for setpoint, other details omitted.

 

[Mattax]

Thanks Kit. I still struggle with the concept of current storage. I need to dust off some books here and see if I can grasp that better.

Funny you mention the trade secret.
Just looking at what's visible in the cutaway we can see they left out a bunch of resistors and caps.

In the Master Tech diagrams, the electronics definately simplified.
This one is clear and, provides the key info that a mechanic needs for troubleshooting.

But some of the others are confusing.
I don't know what happened between the electronics guys, the tech writers, and the illustrators but there it seems like there was a communication breakdown. That's why I started drawing out my own.

Just saw an error in the diagram I said was good.
It makes no difference to the point being made about how the electronics work.
But it can be confusing to anyone trying to understand the system.
Fixed it

 

[KitCarlson]

Yeah, the transistors are neutered, no arrows showing emitters. One on right is darlington NPN power transistor, left is small PNP. 12V Zener diode voltage plus 1.8V will turn on PNP, that shuts off NPN. The 1.8V is total of 3 base to emitter junctions in series.