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BTW, I ended up making a schematic of my (presumably) Auto-Lite VLX6007A voltage regulator.

crcit.net/c/ea3ba00fd4b64cdcbd0d5d201385a586

For those reading this and commenting privately that I've been ignoring comments from humanpotatohybrid, we have actually been having an extended and extremely helpful offline conversation so no worries there!

On the question about mechanical regulators and how polarity can possibly matter to a relay, I found this on a tractor site's blog. I believe some pages back Howard or one of the other posters had made a similar suggestion and it is likely correct and actually makes sense.

Quote:

So for the solid state design and with humanpotatorhybrid's incredible (and incredibly patient) help, I have the printed circuit board designed but only for negative ground so far. It was specifically designed with the '50s or later Delco-Remy regulators in mind but I am going to have to compress it considerably to fit into an Autolite housing which may be a challenge!

Now to try to come up with a positive ground version . . .

Certainly it has been "extended", as I count, we're up to 123 emails in the chain.

I'm designing a universal solid-state regulator, that supports 6V or 12V, positive or negative ground, and self-energized or externally-energized generators, and up to 50A or current, with selectable current limiting.

Soon I'll be finishing up the rough schematic, with all components placed but exact choices and values unassigned, which I'm planning to post on here. Then I'll go back through and try to make it a complete design. Then at some point try to do a PCB of it.

Alright, this is what I have so far for a schematic. This is for positive or negative ground, 20/30/40/50A selectable current regulation, and 6/12V (7/14V) voltage regulation. This one is only for self-excited generators, the only type that Packard used AFAIK. Though this could be modified without much difficulty to accommodate separately-excited, or even both on the same design, the chance of swapping generator types on the same car is so small, to one that Packard never used, that it's not a design priority. That being said, this design is not Packard-exclusive, and should work with any car with a self-excited generator.

If you're not familiar with the difference between self- and separately-energized generators, read this parenthesis:
As I understand it, there are two basic types of shunt-type car generators. If the generator field is connected to arm internally and the regulator adjusts the resistance between the field terminal and ground, then it's a self-excited generator. If the field is grounded internally and the regulator adjusts the voltage provided to the field terminal, then it's a "separately excited" generator.
According to the service book, '55 (and I assume most/all other) Packards used the former. One can tell by excerpts of the manual: self-energizing will increase output when F is grounded. Separately-energized will decrease output. Note that this is regardless of voltage or polarity (assuming that all the correct polarity components are being used).

Anyway, on the schematic:
- To connect it, connect BAT to the "ARM" of whatever type of ground the car has. For example, on a negative ground car, connect BAT to "ARM –". Then connect generator ARM to the other "ARM" terminal. For FLD, ground the "FLD" of whatever type of ground the car has. Then connect generator FLD to the other "FLD" terminal.
- The DPDT switch near the bottom is for 6/12V selection.
- The SP4T switch near the center (modeled as an IC) is for current selection.
- The "MLX" IC is an ammeter, which outputs a voltage on Vout proportional to the amperage.
- The transistors near the bottom are there to get the voltage read from the actual armature sie, regardless of type of grounding, and to avoid a short circuit around the ammeter and Schottky diodes (which would occur if just diodes were used).
- Two different ground symbols are used: the "lined" ground is chassis ground; the "triangle" ground is only to mark in common some connections on the board, and is not directly connected to the car ground. This is because the electronics would not work with opposite grounding otherwise; the car's current is rectified and then sent to the electronics that require it.

Very complicated-looking, I know; it was hard to clean up the schematic. But I think the design is solid enough with hopefully no or few errors at this point, just details that need added. Sometime soon I'll be finishing up the exact component choices and trying to breadboard it.

Interesting and rather clean looking design! Since negative/positive ground is not an automatic thing, will it have protection if set one way and accidentally connected the other?

On the unlined ground symbols, I take it to mean that they are common rather than ground. Is that so? You said that but I just wanted to be clear.

For the arm, it's not shown, but an inline fuse 5-10A above the amperage rating would be suggested. If connected backwards, it would basically be shorting Arm to Bat which... would probably just drain the battery (assuming the car is off). May well damage the generator and/or regulator though.

For reversing the FLD terminals: Looking again I don't think I'll need an optocoupler over just a transistor or similar, probably an IGBT. For the IGBT's I'm looking at, it would either limit charging, or remove the limit on charging, depending on whether the IGBT has a reverse-biased diode built in. I'll probably select a component without one, to give the former result.

Yeah the triangle ones just indicate a common connection.

I've made some headway on my design with a couple prototype printed circuit boards (PCBs) having been made. The unit is comprised of two boards: one shown here which contains the regulator circuitry and another daughter board below it that is not shown which maps the connections to the proper place in the housing. This will allow the regulator to work with different housings and external connection location.

What you see here attached to an assembly support (it makes soldering easier) is incomplete and was just a trial fit but a couple components ended up being larger than expected so a new board is being made.

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Looks like it is coming along nicely!

Thank you but this board is a dud so using it only for testing fitment and there are a couple things which simply do not fit at all. I would also love to see yours made as it seems more universal than this one and I am getting to be something of an expert on the software for designing the boards!

After considerable time, I am working on this again with the main delay in having moved from Silicon Valley to coastal Santa Cruz where getting to the laser cutting shop that I use was much farther.

That said, I finally managed to go there last week to have a couple of the Delco-Remy regulator bases cut out for the mounting of the regulator and to have the contact arms cut. This is only a prototype and totally untested which brings up the question of how to do it. The only Packard I have with the Delco-Remy mounting holes is my 1954 Patrician which, of course, is positive ground. So, if I were to temporarily reverse the battery polarity for testing, would the solid state regulator be damaged by polarizing the generator?

Shown here, the main regulator is just sitting loosely in place and obviously the same with the daughter board and connectors. Ultimately if more are made, I will make all the steel connectors the same so as to cut the cost because making three different ones was expensive!

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