Voltage regulator (Motorola)

Can't think straight in the heat. Stock Motorola alternator on a combine.The regulator is just a little oblong box with one wire in and one wire out. No rubber mounts. Does it need to be grounded good where it mounts to the side of the cab,or is one bolt on a painted surface good enough? It isn't working and I'm wondering if that's the problem? I was gonna go to a Delco self exiter,but not sure it will bolt up to the mounts on the motor now. Hate to cobble things too bad.

The regulator HAS to have a good ground.

What combine?

I'm VERY familiar with Motorola alternators, but the regulator, as you describe it, seems "odd".

If it is, in fact, the regulator, (with the engine running) there needs to be battery voltage on the wire INTO the regulator, and (if battery charging is needed) there needs to be battery voltage coming out of the regulator, going to the "F" (Field) terminal on the alternator. As the battery comes up to voltage the voltage going to the "F" terminal will drop.

Check that out and post back. A photo of the alt and reg would be helpful.

I went out and traced everything down. I can see that that regulator isn't stock on that combine,the paint is a different color where the original was. It was larger. I don't have any other wires hanging though. It's a 1972 Oliver 7300 gas with the 318 Chrysler V8 gas.
There are only 2 wires going to the alternator. A red wire from the amp guage to the big lug on the alternator. That's the wire that would hook to a self exiter. The other wire plugs on to a spade on a little plate that's hooked to the back of the alternator with a screw. A wire loops from there to a stud on the alternator marked "fld" (field).
Now,on that regulator,it's stamped right in the cover "fld" and "ign" The fld wire from the alternator is hooked to the fld post on the regulator. The wire from the "ign" side plugs on to a panel with 7 wires hooked to it under the instrument panel.
Just an aside,my White 2-135 tractor had just 2 wires going to the Motorola alternator. I couldn't tell you how many are on the regulator,I don't even know where it is,BUT,I changed that one to a Delco self exiter a few months ago,and the guy at the starter shop said that second wire to the alternator was just an exiter wire and told me to just tape it up and leave it unhooked. I did,and that one works just fine.

Are you SURE it's not a Mopar alternator?

ANYHOW, as I posted before, check the voltage into and out of the regulator. If the field IS at near battery voltage and the alternator isn't charging it's guts out, the alternator has failed.

No,I'm not sure. Could be a Mopar. The only way to get to it is lay across the top of the motor and I can't see any tag or numbers. It isn't made like the Motorola on the tractor,that's the problem with changing to a Delco. The Delco and the Motorola on the tractor both had a solid bolt hole all the way through where they bolt on. This one had 2 short mounting holes,one at each end with the bolt exposed in the middle. Trouble is,one of those tabs (for lack of a better way to put it) is in front of the mounting bracket on the motor instead of both being inside the bracket. Don't really want to void my warantee by grinding or cutting on the Delco.
It should charge the heck out if it if I hook a jumper wire around the regulator shouldn't it? That is,if the alternator is any good.

what you describe sounds right according to the manual for the white 7300. Red wire should go from "bat" on alternator to "-" on ammeter; brown should go from "fld" on alternator to "fld" on voltage regulator; another wire runs from "ign" on regulator to terminal block; and there is a jumper wire from "fld" to "grd" on alternator.

in the parts book i see there were a few different alternators and regulators used depending on serial number of engine.

again, this is all out of my white 7300 books, but i assume the machines are the same except for the decals

With those little mounting tabs it DOES sound like a Mopar (meaning a replacement should be readily available and reasonably priced at an auto parts store so there's no reason to try to "reinvent the wheel" and change it out to a Delco.

And, yes it SHOULD charge like a bugger when "full-fielded".

P.S.... If it doesn't charge when full-fielded, first check the brushes, which are readily accessible (and easily replaced) without dismantling the alternator.

I gave up and took it to the starter shop. The boss was gone,but his sidekick tested it. Didn't seem to be working,BUT,he had six or seven there in boxes that he must have gotten a deal on. He tested those. One was putting out just 12 volts,2 were discharging and the rest didn't do anything,so he wasn't sure he was doing it right. He said the boss would be back Monday,so I guess I'll sit on my hands til then. Blasted thing won't run anyway. Can't get gas up to the carb and they won't have a fuel pump for it til tomorrow morning.

If it's a Mopar/ Chrysler Alt . the Pulley is pressed on ,every other brand has a nut look inside the pully and see if its got a nut.
.Your description sounds like the reg is a Mopar .

be careful if you use a jumper. It won't take very long to burn up the alternator. With a 7 ohm resistor you can let it run all the time but it will boil your battery when it reaches full charge.