1930 field coil wiring
 

I have a '30 coupe with a charging problem. I took the generator off and took it apart. The cutout is like new but the coils are fried. Prior to removing the generator I checked the ground and there wasn't any. Rusty connections where it bolts to the block. All that will be taken care of. Got new coils and a few extra parts and am now putting it back together. Needless to say but the wiring was pretty well thrashed so not sure how it should go back together. The coils came wired together. When I was taking the old ones out of the frame, there was one wire that came up through the hole at the cutout and connected to the cutout at the back side at the hole end. The wire from the other coil was down inside of the frame so I don't know where it was attached. I've searched everywhere but can't seem to find any pictures on where every wire should go. To the best of my knowledge, one coil wire goes to the 1st brush holder, the other coil wire goes to the 3rd brush holder. This is where the trail ends. From ordering parts it looks like there should be a wire with a stud that goes up through the hole that comes out near the cutout and the other end goes somewhere? I'm not really stupid, maybe a little ignorant, but I could use a little help.

Thanks for any help finding a good map of where all of the connections should be.

Jim

Re: 1930 field coil wiring
 

http://www.webjunk.com/modela/wp-con...amcolor2sm.jpg

For a general sense of what connects to what.

Joe K

Re: 1930 field coil wiring
 

Thanks for the reply,

I've seen that quite a few times but it's too vague for me. The wire going to the cutout could be going to ground. It also shows one coil going to ground which I don't think is correct, at least from what I've read. One is supposed to go to the 1st brush and the other is supposed to go to the 3rd brush. The 2nd set of brushes are supposed to be grounded.

Jim

Re: 1930 field coil wiring
 

Here is a couple pictures Tom posted.

Bob

Re: 1930 field coil wiring
 

Thanks for posting them again Bob.
Sometimes the field windings are grounded by a screw in a threaded hole in the case, and some are grounded by a large eyelet terminal held tight to the generator case by the insulating washer on the output stud.

Re: 1930 field coil wiring
 

If you've got a Brattons catalog, look on page 66. There is an exploded diagram. The wiring legend is at the left side bottom of page. You have 2 wires coming off the field coils The wire with the large eyelet terminal end as Tom says above is the ground. the other field coil wire connects under the third brush screw. The terminal lead wire connects under the insulated main brush screw. If you have the generator with 2 wires that extend through a hole in the tube part of the housing, you have the model 46 generator. The Model 46 generator was used with 1933 and later four cylinder engines. This was sold as a replacement for the model A generator. Usually when I rebuild this style generator, I install a terminal post like the model A generator used. the wire from this terminal post should connect under the screw on the insulated main brush screw. Originally the model 46 had the field coil ground wire grounding under the mounting leg of the cutout. I ground them inside the housing like the model A generator. The generators are very similiar, one has an outside ground wire and no terminal post. the model A generator grounds internally. If you've got the Brattons catalog it will show all of what I speak of.

Re: 1930 field coil wiring
 

Tom,

You sound like the man I need to talk to. According to what I've read, one lead from the coil goes to one set on brushes and the other end goes to another set of brushes. How does the energy get out of the generator. Does a jumper wire go up to the cutout or ground? I'm kind of dense in that I need a picture of the actual wiring to understand what's going on. Is there an insulated stud that goes through the generator? I don't have the cutout in front of me but it seems like it has a connection that comes out the back but it seems to be grounded. What wire goes to the front of the cutout other than the black and yellow wire from the firewall?

Jim

Re: 1930 field coil wiring
 

Prudy,

Thank you! I'm going to look up the article you're talking about. That sounds like what I've been looking for.

Jim

Re: 1930 field coil wiring
 

A little more focused pic;

Re: 1930 field coil wiring
 

That's the pix I referenced above.

One brush is grounded. The other brush comes out of the top of the case and is (-) (positive ground system.)

Meanwhile the third brush feeds the field coils which are set up in series. The only trick to the field coils is that they have to be wound the same way, otherwise magnetically one will cancel the other out. And the other end of the wire after the second field coil is grounded as well.

A compass can help you find out if the polarity of the field cancels out. If one or the other poles of the field attract the SAME end of the needle on a compass, then they're bucking each other.

Joe K

Re: 1930 field coil wiring
 

Joe,

So where does the (-) wire that comes out of the frame attaché and to what?
Sorry I'm so dense but it's really simple to someone that knows what's going on, but to someone that's not familiar with it, there's a big problem.
Oh! Bye the way, I noticed you're a Senior Member. I'm 78 and will be 79 in 3 months and am listed as a Junior member, how old do you have to be to be a Senior member?


Jim

Re: 1930 field coil wiring
 

On a model A generator there is only the output terminal as shown on either the complete wiring diagram or just the generator section. There is no second wire on the model A generator that leaves the generator. The case is grounded.

Re: 1930 field coil wiring
 

If you have a stud coming out of the case, then it MUST be insulated, and a short wire also connects this stud to the INSULATED brush mounted on the end plate. The brush holder that isn't insulated is the ground brush for the commutator, which is the + ground.

Also note in Mike's picture the field wire on the far right has an arrow on the end of the wire. That symbol denotes GROUND, and that end of the wire is grounded under a small screw in the case, or it's held tight to the case by the insulating washer on the output stud.

With the rear of the generator facing up and the output stud facing away from you, you can connect a battery or 6 volt charger to the field windings (+ ground) and the compass needle will point north to the left, no matter if it's on the left side, the middle, or the right side of the case.

Re: 1930 field coil wiring
 

The wire that comes through the side of the generator attaches to the inlet of the cutout. You can see in Tom's pix above the black plastic bushing and (usually) a copper bolt and nut used to make the pass-through. It all attaches to the cutout on the outside. Cutout usually marked 'gen' on the side from the generator and 'bat' on the side connecting ultimately to the battery - but not always.

Most commonly the cutout has two feet that slide "one way" while being attached and a forked electrical connection in the middle on that side such that all three bolted connections are made at the same time and similarly. But the centermost one on the side of the cutout attaches to the copper bolt/nut electrical path mentioned. You'll note this centermost cutout connection has a little insulator too and thereby you can tell this is the electrical path.

I think "senior" is awarded on the basis of the number of posts - and not necessarily one's age. As I have seen SEVERAL age 39 birthdays - but not as many as you.

And not dense. The only stupid questions are the ones that are not asked.

Surf around the site. Search on "cutout" and you should find lots of pix showing the general vicinity around this device. For me pix are EVERYTHING (I'm a "visual" person.)

Hope this helps,
Joe K

Re: 1930 field coil wiring
 

Thanks to all,

I'll go to "School" tomorrow and try and sort out all of the info from today. Thanks again, and I also am a "visual" person. Really dense until I completely understand something and then you never forget.

Jim

Re: 1930 field coil wiring
 

Ah! Ha!, It's starting to make a little sense. The part that was missing from my generator was the lead from the (-) brush up through the case to the cutout. I kept trying to figure a way for the coil wire to attach to the brush and still get to the cutout. I was always coming up one wire short. I'll try and put all of this knowledge to work and should be hearing it purr by tonight.

Thanks all,

Jim

Re: 1930 field coil wiring
 

I don't think this has been mentioned but if you have wires coming
out of the generator housing you have a Model B generator. They
had two wires instead of a stud hooked to the cut-out.

Bob