1918 E49 Buick generator- another question

[Doug Ruth]

View of motor generator showing 3 terminals, but only 2 of which are shown in the shop manual. See photograph attached. My previous question about the terminal 2 connection was answered correctly in that it makes the motor slow down so as to engage the gears better but is also is needed for the generator to work when the car is running. However, with it disconnected the starter goes a lot faster and makes it easier to start the engine but then it has to be re-connected to keep the battery charged. Am I missing something here? Anyway what is the third terminal for?

 

 

 

[DonMicheletti]

That terminal is on th wiring diagram but hard to decypher.

It is a lead to the ignition coil that goes through the "shunt field". Is a lead to/from  the coil. You'll see two wires to the coil. One from the S/G (your mystery terminal) the other from th combination switch, both terminating at the coil.

 

Confusing?

[Oldtech]

I think you need both wires for it to motor. 

[Morgan Wright]

Before I go to my unheated garage to look at my car, do you understand it's -18 degrees F and 30 MPH winds? I'm wearing pajamas.

 

I'll go around midnight it will be -24

Edited February 4 by Morgan Wright (see edit history)

[Oldtech]

You realize we just send our weather down to you guys. 3 days later. 

[Morgan Wright]

You can keep this weather up there.

 

I just went out and looked at my E-49. The red wire in your pic goes to the ammeter, on my car that's how it looks, the ammeter wire comes from the big starter terminal that the positive battery wire attaches to, a second terminal goes up to the #2 ignition switch, but I don't have that third terminal.

 

The wire that goes from the starter to the coil that Don was talking about, on my car, just comes right out of the starter without a terminal. Yours looks different from mine. Do you have a wire that comes out of the starter with no terminal that goes to the coil? If not, then that's probably what your unknown wire is for, I don't know why yours looks different.

[DonMicheletti]

Mine is like Morgans with the wire coming out of the S/G to the coil terminal - no terminal at the S/G.

I have seen others that way too (photo of original one I rebuilt - different exit location too))

[DonMicheletti]

Another photo taken further down the road showing where that wire goes to the field coil

[Morgan Wright]

Mine looks like Don's

 

.

[jbbuick22]

I think you have a newer s/g a delco #184 1921&1922. 1918 should be a delco 117

 

The 184 has the 2 terminals one goes to ampmeter the other to +ign coil

 

JB

[jbbuick22]

The number is on the case facing the frame rail

 

JB

 

[Morgan Wright]

 

 

Positive battery cable and ammeter wire both go to the same terminal (big one)

Other terminal is #2

Coil to S/G wire has no terminal

 

 

.

Edited February 4 by Morgan Wright (see edit history)

[Peter R.]

[Peter R.]

[Peter R.]

[DonMicheletti]

Peter,

 

Exactly what Morgan and I were trying to say.

 

Those are great wiring diagrams and photos. 

The "E" series cars have a different combination switch than the later cars, but accomplish the same thing

[Doug Ruth]

For whatever reason our mg does not look like any of the above. With ours the coil gets power from a wire from the #4 terminal on the switch panel on the dash as pictured in our shop manual wiring diagram, which i do not have in front of me here. As mentioned, the third terminal does not seem to do anything as everything works without it being connected to anything. I will look for part number on the unit next time I am in the shop (Thursdays).

Thanks to all who have supplied information.

[DonMicheletti]

If it does everything it should, you are OK.

An easy way to see where the terminals are connected inside is to remove the cap from the field coil and brush end and see just where things go.

 

It would be interesting to see what you find.

[Morgan Wright]

19 hours ago, Doug Ruth said:

With ours the coil gets power from a wire from the #4 terminal on the switch panel on the dash as pictured in our shop manual wiring diagram,

Both wires attach to the same peg on the coil. The one from #4 and the one from the S/G. 

 

.

 

Edited February 6 by Morgan Wright
make a new post of it (see edit history)

[Morgan Wright]

That coil post needs 2 wires, one from the battery to start the car and the other from the generator to save the battery and charge it back up. The wire from #4 is essentially "from the battery" because it's hot when the car's not running. But if you don't attach the field wire somewhere, how does the battery get re-charged? You say everything works the way it is, but does the generator charge the battery?

[dibarlaw]

Again many thanks to Peter for including the DELCO diagrams. There is some detail information that was not known otherwise just using the Buick provided references. Particuarly, what models were to have which combination switch.

 This covers my 2 Buicks as I have a 1925-45 that still takes the 1924 #268 S/G. My 1925-25 that takes the #283 S/G.

[Doug Ruth]

Per the factory manual diagram the coil gets voltage from the 4 terminal when the switch is pulled out. The s/g wire is attached in parallel with the hot battery lead also part of that switch, as shown in the shop wiring diagram. As long as that wire is attached to the 2 terminal the gen will charge. Putting on the coil terminal is the same as it being on the 4 terminal where it is supposed to be. Ours works just fine except when the sg is connected to the 2 terminal, essentially the same as the battery terminal the starter runs very slow as it is supposed to but it makes it harder to start the car, so we don't attach it and the motor runs happily along at full tilt. We then connect the sg wire to get 6 volts to it and then the gen generates. 

[Rod Wise]

Doug,   The starter motor and the motor/generator are two separate circuit's. You should not need to disconnect the motor/generator wire when pushing the starter pedal for the starter motor to operate properly.  When you press the starter pedal the motor /generator brushes disengage and the starter motor brushes engage.  When you release the pedal the starter brushes disengage and the motor/generator brushes engage.

Possibly the motor/generator brushes are not disengaging properly when the starter pedal is being depressed.

If the brushes have been replaced maybe they are too long and not disengaging properly.

The coil is not your problem but here is a diagram of the model 2158 coil.

[Morgan Wright]

It's true that #2 and #4 are basically the same, they are wires from the ignition switch, but all their juice comes from the battery. The field wire, which in my pictures and Don's as well as Peter R's, comes out of the generator without any terminal, and only carries juice when the car is running and the generator is turning and the foot is off the starter button so the generator brushes are engaged. That's the wire that charges the battery. It must be attached to #2 or #4 either one doesn't matter, but the standard way is to attach it to where the #4 wire goes at the coil. Don suggested you open the S/G to see what attaches to that extra third terminal you have. If you find that it has a wire that goes to the field coil inside the generator, then that's your field wire and you need to run a wire from it, at your extra terminal, to the coil to join the #4 terminal wire, so your battery will charge.