1950s 1957 generator regulator (pictures added)

[Carcadillac]

Charge light turns on solid bright when rev engine.  Doesnt seem to charge on idle.  Dive into manual check specs such as contact gaps, power test alt on bench. 3 Underneath coils" id imagine shouldnt be dirty? Assume outside capacitor" should be changed. 1957 A/C w/ radio/power antennae 4bbl carb.  Any experienced notice any issues?  Ignition system works properly. Will run it pull battery cable off see if it stays on as well. 

[Michael Petti]

I had this same issue about 1 year ago. It turned out to be the generator that was not putting out enough current. It put out 13.5 volts. NAPA told me needs to be 14.5. Maybe that is your issue. I had the generator rebuilt and the regulator cleaned, tested and adjusted with it by the rebuilder and the problem went away. Your capacitor looks rusty so it could stand being replaced. Let us know what happens. Clean all the connections too.

[dplotkin]

I believe you have a "double contact" regulator which was used with AC cars. Looks to me as though the upper contact or circuit is open, as it charges on the lower contacts at low speeds. The "coils" on the backside are resistors. The regulator does its job by sending field current through the resistors, or not, as vibrating contact(s).

You could have an open resistor or more likely an oxidized or burnt contact(s)

These regulators were considered consumable devices back in the day, 40,000-50,000 miles they would give, most often back then when a generator was rebuilt the regulator was changed. They can be adjusted but not repaired.

I had the same failure on my 60 Electra with its original 43,000 mile regulator. You will need another one. I was able to source a double contact regulator, I'll look to see where from and let you know.

Dan

[Carcadillac]

I see few options for regulator but top cover bolts in different positions than this one.  The condenser" 1917580 doesn't seem to xref, corvette central seems to offer same one "radio capacitor". Ignition coil has condenser, alternator does not.  Napa lists a alternator condenser pn: ECH RR175 not sure what mf rating is. Probably wise to do alternator and regulator at this point.

Ran it with regulator cover off and no movement on BAT contact at idle, nor revved. Field terminal @ reg contact moves up/down. Cleaned up contacts" and wire connectors, Drops below 12v when turn on parking and headlights idle/revved.  Cleaned up wire connects from Gen to Reg and made sure signal end to end(disconnected from battery).  Get 14.5V at Reg gen terminal when its running. No dice on adjusting Bat contact closer.  Thanks

Bat appears to have 1 pair contacts, Gen 1 pair, field 2 contacts ones either opened or closed.   

Lower contacts make contact when off.  two upper do not (Bat/Field).

[bcroe]

The first thing to check is the generator brushes. 
I used to go thru a set every year.  While it is
out check for good connections and the front bearing. 

That cap reduces radio interference, but is not
related to gen output.  Bruce Roe

[Carcadillac]

Replaced the regulator with napa unit and it charges.