Calling all charging system gurus!!!!

C5rider · #1 03-12-2013, 05:55 PM

I've got a quick couple of questions for you.

I'm working on my Original's charging system. It's VERY basic, with only about 5-6 wires!

I bought the tractor a couple of weeks ago so I have no background on the tractor at all. I started checking the system and the S/G would start the engine, but it wouldn't charge. I suspected the wiring was at least part of the problem. I was right.

I checked the system per R. Bedell's excellent schematic and some of the wires were not hooked up. Now, with everything where it should be, the S/G is constantly charging at 16.5v-17v when I rev the engine up. The Field terminal on the regulator is constantly grounded. I'm thinking that the regulator ISN'T regulating.

I know that there are contacts inside the regulator and I'm wondering if maybe one of the contacts is stuck closed, thereby constantly grounding the field terminal? It is grounded right at the regulator.

I have another regulator from another tractor, but the soft-metal wire (wraps around two poles inside the regulator and acts like a fuse, I believe) is burned. If this soft metal wire (fuse) is replaceable, I would swap out the regulators and see if that helps. If it's not, I'll have to get another one, or figure out how to fix the one currently on the tractor.

If I remember correctly, there is also a way to adjust those regulators. Anyone know?

I put in a new battery and I'd hate to smoke it due to over-charging.

Any insights would be greatly appreciated. Thanks!

C5rider · #2 03-12-2013, 10:04 PM

No hassle at all...

I did a little 'vestigatin' and noted the adjustment screw on the spring of the magnetic coil that grounds the fields pole on the S/G. I screwed it out to where the points were not touching (no spring pressure) and then fired up the tractor. I slowly screwed it in with the revs up until I saw 13.7-14v on the digital meter.

I'll be checking it on occasion to make sure that is exactly where it should be. On the other side of the coin, I learned a little bit more about my Cub today!

ol'George · #3 03-12-2013, 11:38 PM

Quote:

Originally Posted by C5rider

I've got a quick couple of questions for you.

I'm working on my Original's charging system. It's VERY basic, with only about 5-6 wires!

I bought the tractor a couple of weeks ago so I have no background on the tractor at all. I started checking the system and the S/G would start the engine, but it wouldn't charge. I suspected the wiring was at least part of the problem. I was right.

I checked the system per R. Bedell's excellent schematic and some of the wires were not hooked up. Now, with everything where it should be, the S/G is constantly charging at 16.5v-17v when I rev the engine up. The Field terminal on the regulator is constantly grounded. I'm thinking that the regulator ISN'T regulating.

I know that there are contacts inside the regulator and I'm wondering if maybe one of the contacts is stuck closed, thereby constantly grounding the field terminal? It is grounded right at the regulator.

I have another regulator from another tractor, but the soft-metal wire (wraps around two poles inside the regulator and acts like a fuse, I believe) is burned. If this soft metal wire (fuse) is replaceable, I would swap out the regulators and see if that helps. If it's not, I'll have to get another one, or figure out how to fix the one currently on the tractor.

If I remember correctly, there is also a way to adjust those regulators. Anyone know?

I put in a new battery and I'd hate to smoke it due to over-charging.

Any insights would be greatly appreciated. Thanks!

That is not a fuse, it is a wire wound resistor! Regulators have no fuses inside/outside. Ya you can adjust a regulator, BUT not recommended as they are set @ the factory in a temp/humidity controlled environment. That said, I have back in my young days in the '50's adjusted them because of lack of funds, and sometimes you get lucky if you don't move them much. Some regs back in the day, did have an external adjustment screw/knob that was marked more/less charge.

C5rider · #4 03-13-2013, 05:53 AM

Ol' George,

not talking about the resistor under the regulator, there's a "wire" inside that I was speaking of. I'll take a photo of it today.

mickb72 · #5 03-13-2013, 06:44 AM

Hi C5, Good job adj that v/r, hope it keeps working. I/ve looked in a lot of v/r. Those wires inside you speak of, some i've seen are thick and some are hair like thin. Must be for different current carrying ? A lot of them are marked inside, 13.?, 14.? 7.?. I have some off 6 volt fords. Good luck Mike

C5rider · #6 03-13-2013, 08:54 AM

Here's a picture of that wire. It's just wrapped around the posts at each end. It reminds me a lot of a fusable link-type of wire. I have good reason to believe that this regulator is good, save for this one wire that is burned through. I'm sure that it has a specific value for the right amount of protection so I don't want to "put a gum wrapper around it" so to speak.

The newly adjusted regulator is working fine. Hopefully, continues to do so. But, if it should ever decide to take a dump, I'll hopefully have this one ready as its replacement.

save_old_iron · #7 03-13-2013, 10:48 PM

C5,

The wire you call out on your regulator is just plain old solid 18- 22AWG hookup wire. As was mentioned ealrier, there are no "protective" devices or fuseable links inside the regulator (but fusing the SG really isn't such a bad idea.)

Here is another view of the same regulator.

The wire connecting the relay to the terminal is probably to support field current (I'll have to check and get back to you). In either case, field current or relay voltage sense function, #18 - #22 AWG wire should be fine.

The relay to the left is the current sense relay. Note the much larger physical size of the wiring wrapped on this relay. The current limit relay activates from the magnetic force developed by a few wraps of larger gauge wire carrying up to 15 amps of current .

The voltage control relay consists of hundreds of wraps of smaller gauge wire whose function is to respond to the voltage present across its contacts.

Either relay, when activated, can remove the ground from the field of the generator - shutting down power production. In order to keep the generator from slamming full on to full off, a power resistor or resistor(s) in some setups (shown below)

allow a minimal amount of field current to flow even when the regulator cuts off the ground to the generator. With the power resistors functioning properly, the generator is either full on or "somewhat" on - never fully off.

.

C5rider · #8 03-14-2013, 04:56 AM

Thank you for the info Save_old_iron!

That was VERY helpful and informative.

C5rider · #9 03-14-2013, 05:57 PM

I had a bearing that was simply SCREAMIN' at me to change it. So, I did.

When I put it back together yesterday, I had a nice, clean 13.8-14v at the battery when charging (rev'd up). I checked it today, and NADA!

I have 12.4v at the battery at all times. When I check it at the "A" terminal, I only get about .8v. When I ground out the "F" terminal, I get around 1.6-2v at the "A" terminal.

I bench-tested the S/G, and have 8 ohms between the "A" and "F" terminals. I checked the brushes and they are making good contact. Wires inside look to be solid, with no abrasions or breaks. The fact that the "F" terminal does make a difference makes me think that the field side IS working. The tractor does start fine, just doesn't charge. Grounding the "F" terminal bypasses the regulator, correct? So, THAT shouldn't be an issue.

I DID have a good charge yesterday. The fact that I was inside the generator/starter to replace the bearing would make me suspect that my fat fingers most likely had something to do with it, but it DID work after I removed my fat fingers!

Could a field coil have a short/open? I cleaned out the housing/armature so, could carbon have something to do with it.

Any thoughts?

Sincerely,
Chargeless in Florida...

R Bedell · #10 03-14-2013, 06:06 PM

In order for the charging circuit to work, you have to have a good ground. With a VOM or DVM, you should have and see, zero (or near zero) ohms from the S/G Mount to the GRD terminal on the V/R.

BTW....the S/G puts out about 15 Amps worth of power. It would need a minimum of 14GA wire for proper conduction.