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Are there any solid state voltage regulators available for negative-ground 12 volt GM trucks with generators?

welcome to the garage, kell - got any truck pictures for us? we always like to see more trucks - solid state? ya mean to replace the tubes w/ transistors? a regulator is a simple set of contacter style relays that make or break circuits depending on the state of the battery and generator - computers, which would be the 'solid state' equivelent, are for new rigs or for visiting the Stovebolt page - the replacement for the generator/regulator combination is an alternator/regulator combination or an internally regulated alternator - original style replacement regulators are also readily available, especially for 12V

Bill

Got a 1973 International Harvester Scout II and a 1952 panhead. No pix of the Scout but you can see the bike at

http://community.webshots.com/user/kellrobinson

Now let me explain about the voltage regulator. The panhead has a 12 volt generator, and the voltage gets regulated through the ground connection of the field same as the voltage regulation on old GM vehicles. The Harley aftermarket has come out with solid-state (transistorized) regulators that replace the original mechanical regulators. But the price is high. So I thought I'd look for a solid state replacement voltage regulator to an old GM truck so I could use it on my bike. I'm sure it would be cheaper than what the Harley aftermarket vendors charge for a voltage regulator ($83). And replacing the generator with an alternator would cost something like four or five hundred dollars, so that's not an option.

Anyway, I'm big on upgrading old mechanical stuff with electronics. I even build my own electronic ignitions.

well good luck w/ it - nice lookin scoot - regulators cost about the same for an old truck, alternators less than reg and gen combined - if you design something, some folks here might be interested, tho we're mostly dinosaurs that prefer to recondition the original bits

Bill

just googled the subject - these guys say $40

Found something for $10 at JC Whitney that looks promising:
http://www.jcwhitney.com/autoparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2005029/showCustom-0/p-2005029/N-111+10714+600001361/c-10614

That looks like a hot tip. I just paid $30 for an off-brand regulator for my yarddog with a Cadillac alternator. The Delco was even more.

Hi, Kell!
Those JC Whitney units are for alternators, not generators, so I doubt if they'd be useful in your situation. Is your Harley 6V or 12V? Also, does it have a conventional-type regulator with 3 units, or does it only have a cutout relay and a voltage regulator? Drop me an email, and we might be able to collaborate on something. My brother is an electrical engineer who designs solid-state stuff for the automotive industry.

Edit: I just noticed it's a 12V. That helps!
Jerry

I bought a Delco 10si alternator at autozone for $25 + core with a 3 year warranty, and they let me choose how I wanted it clocked, too. I know some originality is nice but an alternator works way better than a gen, even with an electronic voltage regulator.

However:
I'm willing to help out with a Stovebolt solid state regulator kit design if someone wants to collaborate with me on the assembly and packaging.

I have a stovebolt and am an electrical engineer, as well as free access to Tektronix's entire reportiore of test equipment.

The regulator should be a simple matter of a 50 amp power FET for the Gen cutout, a current sensing circuit (for the overcurrent cutout), and a voltage regulator circuit which controls the field of the generator. It should cost about $20 in parts for small quantities. It could even be made to work with both 6 and 12V designs and positive or negative ground with a little re-configuration.

I'd be interested in collaborating. Universal with selectable 6,12,24V and overcurrent. I'd pondered a similar setup for my 24V systems but the mechanical regulator has been very reliable.

Ok I will admit I don't know bean about motorcycles but why not just use an transisterized version of the old Regulators? They had them 10 years ago when I sold auto parts. They were smaller then the originals. But I am sure that there is something that would prevent you from doing this otherwise you guys would be doing this right?

Yes it looks like the JC Whitney regulator is for alts. But with the addition of a high current diode to block the battery from discharging through the coils, that regulator will control a generator. I did that on my bike. I took an extra regulator from a Delco 10 SI alternator I had lying around, added a heavy rectifier and used them to regulate the two-brush twelve volt generator on my Harley, at least until the bike's constant vibrations broke the diode off. I posted a picture of that voltage regulator at the web site link I posted above.

I have a schematic that I found on the web of the Delco regulator. Very simple in principle. I don't have that link, but here is another link to a voltage regulator design for a beemer... it has a different polarity, so to make it work for GM you would have to flip all the transistor polarities. And you would have to add a diode at the armature to make it work with a generator, as I mentioned
http://homepage.sunrise.ch/mysunrise/joerg.hau/mot/voltreg.htm

One thing I have found out about building electronic stuff like that at home, it is extremely time consuming. To make a worthwhile product you would have to go through a development process of prototyping and troubleshooting, then fabbing circuit boards, if you have the experience, or sending out to have them made. I got a little taste of the amateur product development headache with an electronic ignition I make, which I sell in very small volume (like about one unit every two months) through a motorcycle discussion board. It takes all afternoon just to make one or two units, and these is a very simple circuit with just two transistors. But the final result is a beatiful unit sealed inside a piece of seamless square aluminum tubing about the size of a cigarette lighter. For potting compound I use ordinary black silicone rubber door and window sealant in a tube from the hardware store. I tried epoxy, but it caused the circuit to malfunction. You can see a photo of it at the webshots.com link.

Back to voltage regulators... the transistorized version of the 12 volt Harley regulators that are sold by Accel and other vendors would probably work on a GM truck (although it would cost less to use the JCWhitney regulator and a hefty diode). I've never worked on an old GM generator but I think the setup is the same as Harley: the generator has an armature terminal and a field terminal. The charging current comes out of the armature terminal. The regulator determines the armature output by the amount of current it allows to go from the field terminal to ground. This sets up a stronger or weaker magnetic field, allowing for a greater or lesser output power from the armature depending on how much voltage the regulator senses at the battery wire.
One significant difference between the mechanical and solid state regulators: while the mechanical regulators have current limiting, the solid-state ones do not, at least the ones I have seen. So if you have a dying battery that will not hold a charge the generator will put out maximum current in an effort to keep the battery voltage up. Older motorcycle gurus will tell you that a generator can burn out under those conditions.
But it is easy to limit current on a solid state regulator by putting a resistor of a few ohms in the wire that connects the field terminal to the regulator. How big a resistor would have to be determined emprically, but it would be somewhere in the 1 to 10 ohm range.
I'd be interested in collaborating or at least discussing this stuff more, since it looks like there are some EE's on this board. Myself, I'm an engineering school dropout (2 years of mechanical engineering).

You may fabricate a voltage regulator & cut out but you still need a current limitor. A generator is stupid. It will burn itself up if not controlled.

"You may fabricate a voltage regulator & cut out but you still need a current limitor"

Have you ever heard about the trick of using a twelve volt bulb (like an 1156 or something) between field and ground as a "redneck regulator?" The bulb resistance acts to limit current in the field, which gives you a steady output from the generator. With the right bulb, you can get a very good match for the electrical load of your vehicle.

I had to use that trick on my last trip to Vermont when my bike stopped charging.

For a pretty good primer on generator operation, try my article on 6 volt generators in the tech tips section. You've got the basic operation down pat. The residual magnetism in the armature induces a little bit of voltage into the field coils, where the "A" circuit generator routes the voltage out of the Field terminal to the regulator. The vibrating-contact regulator points provide the ground for the field current, or insert a resistance into the circuit. The current regulator is in the "Armature" circuit, and carries the full charging current. When charge current is high enough to open the points, the field circuit gets a resistance inserted, because the current regulator points and the voltage regulator points are in series with each other. One or the other, not both at once, control the field current.

For a full-control electronic regulator to work, some type of current sensor would be needed to prevent overloading the armature during low-battery operation. The resistance of the armature is low enough that brush arcing, or overheating of the windings, or both, is possible when the battery resistance is too low to oppose maximum current flow.
Jerry

With an electronic regulator it's EASY to limit armature output current. Quite simply, you can do it by inserting some resistance in the field. I kind of tried to get that across in my last couple of posts.
So it would make a fairly simple project for someone with a little electrical savvy for example to adapt one of those cheap electronic JCWhitney alternator regulators, which don't have current limiting, to work on a genny. I did that with a spare Delco regulator I had.

One could design a regulator if he thought there was enough of a market. With the old bikes, there actually is a market for electronic regulators. But with trucks, it's so cheap to convert to an alternator and the benefit so great, it would seem there's little reason to spend money on an electronic voltage regulator for a generator, which wouldn't have the same bang for the buck.

Kell,
if limiting the current is as simple as inserting a resistor, don't you think the original regulator would have had that instead of the current limiting points? No, a resistor would affect the entire operating range and would not do the job for you.

No, it works.