Voltage regulator Auto lite Chrysler

Working on a 1943 airport tug with a Chrysler 6 cyl flathead. The genny is charging wild. I am pretty sure it is an A system. When I disconnect the field wire from the genny it quits charging so the field is not grounded internally. When I ground the field terminal on the genny with the engine running it will charge wild like it should with the field dead grounded.

This leaves the regulator as the suspect for the overcharging. Is there anything to be adjusted or do you think the regulator has an internal short somewhere? The battery terminal on the regulator is to our right in the picture, the field is in the center and the armature terminal is to the left which is different arrangement than I am used to but this is what it is.

Check & see if the points on the center one are stuck together.

The center points separate OK. I have not messed with manually moving the points with it running yet but the center points are apart when it is at rest.

That doesn't sound right????????????

The center points are the field.

At rest they will be spring loaded closed. As the voltage increases the magnet coil will pull the points open, removing the field ground, stopping the charging.

With the engine running at sufficient RPM to charge, you should be able to slightly push on the points lever and stop the charge. If it continues to full charge with the points open, look for a shorted to ground condition on the field wire, possibly before the regulator. Try disconnecting the field wire from the regulator, see if the charge stops. Make sure nothing is grounding the field, like a too long screw touching the case, or something behind the regulator shorting it out.

If the charge stops when you push down on the points lever, it could need adjusting. Be sure the regulator case is grounded before making adjustments. To adjust, ever so slightly bend the tab the spring is connected to at the bottom. Less spring tension lowers the voltage, more tension raises the voltage. Be careful and move slowly, take your final voltage readings with the cover back on, it will change the readings. I would shoot for around 7v if it is a 6v system, 13v if 12.

OK thanks for the pointers. Ran out of time but will check it out after I get home.

My bad, the points are closed. I don't know where I got the idea they were open.

(quoted from post at 18:33:41 03/05/21) My bad, the points are closed. I don't know where I got the idea they were open.

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aybe the "idea" came from the fact that one out of the three are open at rest.

I was reading up on some limited voltage regulator information from a Chiltons manual from the 1960s. This manual claimed a high charge can be caused by a short in the generator fields. I eliminated that when the genny stopped charging when I removed the regulator wire from the field terminal. There is no short in the wire from the genny field terminal to the regulator so that is eliminated. Last cause listed in the manual is either a dead short in the regulator or the points spring tension needs to be adjusted. The manual said if the spring tension needs to be adjusted the regulator is close to the end of its life and should be replaced.

So with the engine running at a bit above idle I very lightly lifted the current regulator points and could slow down the charge. First impression is to lighten up the spring pressure to the points. Seems contrary to what should be done to an old spring as old springs tend to get tired. I might be able to play with it some tomorrow.

If that is an old regulator, give it your best to save it.

Before adjusting try filing the contacts with a point file. It's a very thin special file, probably have to order one.

The field contacts constantly arc when the voltage gets up to the set level, so they have a hard life. The arcing causes the surfaces to pit and burn, the file will dress the surfaces if there is enough plating left to dress. Don't use sandpaper!

That is the problem with the new regulators, the alloy on the contacts is very expensive, they shortcut with lesser materials.

Filing might correct the problem, especially if there is a point burned on one of the surfaces. File first, clean with brake or carb or contact cleaner, then adjust the voltage if necessary.