Help with three brush generator

[pmhowe]

I am the proud owner of a new (to me) Series 526 Packard coupe (1928). The car was obviously cherished by the former owner, but it appears to have sat for quite a while and needs sorting. I am slowly doing that.

 

My current problem is that the generator is not charging the battery. Thus, after starting the engine, the ammeter remains slightly negative as a result of the draw by the ignition circuit. This is independent of engine RPMs. The ammeter is sensitive to the electrical accessories, so it is definitely working. When the car is run for short periods - of the order of fifteen minutes or so, the generator shows no evidence of getting hot. 

 

The generator is an Owen - Dyneto model 800 three brush generator with what appears to be a two stage cutoff and voltage regulator.

 

I would appreciate some guidance as how to proceed.

 

Thanks,

 

Phil

 

[edinmass]

That is a cut out/regulator. I expect in 1928 it only used a normal cut out..........look up the correct application. The unit you have came out around 1935 is is too new for the application........in my experience. 

[edinmass]

Yup, 20058 is the Delco cut out you need. Kicks in at 400 rpm. Go back to stock, a simple unit, what you have is known to be a pain in the axx.

[Rusty_OToole]

The first thing I would suspect would be sticking brushes. Make sure they are moving freely and give them a squirt of contact cleaner spray. While you are at it, check if they are worn down. This is assuming it was working before which is may be optimistic.

[DFeeney]

I believe when the car is off the cut out points should be open .  When the engine starts  the points should close depending on battery voltage.  Seeing if they change state  will be the first step in your  trouble shooting.

[Bloo]

That's pretty much it. One tiny nit to pick, it's generator voltage that causes the cutout to pull in. Voltage present on the generator side of the cutout indicates the engine is running and the generator is spinning.

 

It is way easier to hold a relay down than to pull it in in the first place. Also, once the cutout is "pulled in", the battery is connected, so the relay would stay pulled in no matter what. For this reason there is a second winding on the cutout relay that senses current. When current starts flowing the wrong way because the generator is not charging, for instance when you shut the engine off, that second winding pushes instead of pulls and forces the cutout to open.

 

I am talking about plain single-relay cutouts, although that all still holds true for the cutout relay section of a voltage regulator.

 

A couple of hints: First, in case you didn't already know this, never run a third brush system with the battery unhooked. Second, check that fuse under the knurled cap in the voltage regulator.

 

Edited March 18, 2023 by Bloo (see edit history)

[dodge28]

Well Bloo, you said it. why not just use a diode and you do  not have to worry.

[Brass is Best]

Listen to Ed. The Owen Dynetos tend to be sensitive. 

Edited March 18, 2023 by Brass is Best (see edit history)

[Bloo]

9 hours ago, dodge28 said:

Well Bloo, you said it. why not just use a diode and you do  not have to worry.

I see those as a solution looking for a problem. But then again, I have not really had much cutout trouble in my life. I don't think I have ever bought a brand new one. I've cleaned a bunch of dirty points. Somebody must be having cutout trouble though, because those "solid state" cutouts with a silicon diode inside sure are popular.

 

On one hand, the points in a mechanical cutout can stick, but on the other hand the most common failure mode of a silicon diode is a dead short, so the result of a failure would be exactly the same. Either type can work fine though.

 

Edited March 18, 2023 by Bloo (see edit history)

[37_Roadmaster_C]

One thing to remember is the diode cutout replacement causes approximately a .7 volt drop in the charging voltage. While this does not seem to be very much, you need to remember that the older generators were current limited and charging was a large task for them when they were working at their best. That .7 volt drop is about 10% of system voltage and that is a lot in the engineering of the system. Will a diode work, yea kinda. Will it work well, NO!

 

Follow Eds recommendation and put it back to stock. Packard knew how to deign cars!

Edited March 18, 2023 by 37_Roadmaster_C (see edit history)

[chistech]

I run a Peterson internal regulator on my Chevy, three brush generator as it makes it work more like an alternator but I still use a stock delco cutout to transfer the power to the battery. As was said, go back to a simple, stock, regulator.

[kuhner]

Up until about 2 years ago we were able to buy an electronic regulator for our model Ts. They quit making them. 
A few guys started working on building a real voltage regulator from off the shelf parts and even had everything you needed to have a board made. If you are handy with electronics you might be able to build one yourself, I guess it would work in your application, just change the housing. 
The thread is pretty long.

https://www.mtfca.com/phpBB3/viewtopic.php?f=2&t=25609&p=196314&hilit=Voltage+regulator+Electronic+voltage#p196314

[Mark Gregush]

If the generator internal wiring has been changed to convert to the 2 wire cutout, just replacing the current cutout with a single wire cutout, isn't going to work. Could be that because the generator has been sitting for some time, it needs to be flashed to get it going again. 

[pmhowe]

It looks like I have a bigger problem than I thought: I took a more careful look at the cutoff/regulator.

 

The points of the cutoff are fused together. The points on the other section seem to be not badly worn, but their alignment is awful. It is irrelevant, because I am going to toss this unit, but I would think that adjusting those points for better contact would totally alter the calibration.

 

I then removed the generator cover, and found solder splattered about.

Edited March 20, 2023 by pmhowe
spelling errors (see edit history)

[Mark Gregush]

Well that is a big bummer!

[Oldtech]

Oooh it's been warm.  That solder will be from the commutator. Chances are the armature is bad. Is there a good auto electric guy around?

Edited March 21, 2023 by Oldtech (see edit history)

[pmhowe]

Removed the generator from the car to examine it further. I then learned that the bearing at the driven end of the generator was bad - the shaft was loose and the bearing balls did not allow for smooth shaft rotation. 

 

I was also surprised and disappointed in the amount of material that has been removed the commutator by various people over the years (see Picture).

 

Today's project is to build a box in which to ship the generator off to a rebuilder. Then it is back to other parts of the electrical system.

[Tonz]

Prior to taking my 26 Chrysler 50 on the road, I took my Delco 3 brush Genny and battery to my auto electrician who set them up with a drive motor and bench tested them long enough to make sure all was ok. I highly recommend you do this. Happy Days!

He explained in simple terms my car did not have or need a regulator as the engine runs a such a low revs. 35mph is under 2000rpm.

The box mounted on the Genny is simply a cut out, and inside the 3rd brush can be adjusted for more or less charging volts depending on your driving habits (day or night, summer or winter).

He even drew a plus and minus mark on the brush adjustment for me.

This also came with a warning of one big danger with this system. If you run the motor without the battery connected the Genny will power up until it burns out.

As with other idiosyncrasies of this old car things such as thermosyphon cooling, vacuum fuel pump, no front brakes, basic electrics they are so basic and simple but work so damm well, I often wonder how😆