The Stovebolt Site Forums The Shop Area The Electrical Bay Discharge ---- Charge

Before you condemn the regulator, at least open it up and inspect things. The set of points behind the Bat. terminal are the "cutout relay". They're supposed to be open with the engine off, and should close as soon as the generator develops enough speed to get its voltage higher than the terminal voltage at the battery. They usually close as the voltage at the armature terminal gets to 6.5-7 volts. Closing voltage is adjusted by changing the tension on the spring that holds the points open. More spring tension- - - -higher closing voltage. Once closed, they don't reopen until the generator drops below battery voltage again. This prevents the battery from discharging itself theough the generator. Once it's charging, the generator output is controlled by inserting or removing resistance between the field terminal and ground. A grounded field produces max generator output. The center set of points controls maximum current, usually set to control at 25 amps. At current flows below that amount, the points behind the F terminal control voltage, usually at a maximum of 7.5 volts.

The current regulator OR the voltage regulator will take control, not both at the same time. These sets of points are in series with each other. High current control will happen at a voltage well below the voltage regulator setting, and the voltage points will not begin to take control until the current flow drops beloew the amp limit. Dirty points at either voltage or current position will stop the charge from happening. The current and voltage limits are set by slightly adjusting the spring tension on the points. A small change in spring tension can make a BIG difference in the setting. Use a piece of clean business card or index card to clean regulator points, NEVER a file or sandpaper. The points contact with a slight wiping action to try to self-clean, so the scratches left by even very fine sandpaper will cause them to stick. Stuck regulator points cause current or voltage to increase well beyond their proper settings. NEVER close a cutout relay by hand- - - -you can create a dead short through the generator armature which will burn out the generator, regulator, or both!
Jerry