Solid State Voltage Regulators For 3 Brush Motorcycle Generators


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Solid State Voltage Regulator for Autolite GAS Model Generators


APPLICATION:  This solid state voltage regulator is designed specifically to fit standard output three brush GAS model Autolite generators using a 6 volt negative ground system, positive field winding control and external cutout relay (Standard equipment on Indian motorcycles from 1930 through 1947).


CONSTRUCTION: The sold state regulating components are permanently mounted inside an anodized aluminum housing. This housing is CNC milled to look exactly like the original stamped cover, including accurate �AUTOLITE made in u.s.a.� lettering. The housing also acts as a heat sink for the internal components.  This housing is mounted on a cadmium plated reproduction of the original base.  The end result is a reliable, maintenance free, modern electronic regulating system housed in an exact replica of the original style cutout relay housing.

OVERVIEW OF OPERATION: Installation will eliminate the often troublesome three brush regulating system and mechanical cutout relay. It will be replaced with a solid state current and voltage regulator permanently mounted inside an aluminum housing that looks like the original cutout cover. Installed properly, this regulator will allow complete and accurate current and voltage regulation of the generator, thereby maintaining proper battery charge at all times. Maximum output voltage will be limited to approximately 7.25 volts. Current output will range from approximately .75 amps, up to the maximum allowed by the generator, approximately 15 amps.




  1. A properly functioning Autolite model GAS generator configured for Negative Ground Operation Only.

  2. Elimination of the third brush inside the generator, converting it to a two brush system.

  3. Insertion of a small, hidden control wire from the regulator into the generator.


* 6 volts DC nominal, 7.25 volts maximum output

* 15 amps continuous, 20 amps max, intermittent use

* Negative system ground

* Positive field winding control


TESTING: This regulator has undergone extensive testing over the last 4 years.  Numerous units have been in service on Indian Chiefs and Scouts which have performed perfectly, with no generator, regulator or battery failures reported.  Although no long term field tests have been performed on the battery ignition Indian 4 cylinder, it is the ideal application for this regulator. This is because the 4 cylinder battery model generator turns at engine speed, which limits adequate generator power output to high engine RPM conditions (3000 RPM and above). By controlling field voltage the regulator will allow maximum generator output at much lower engine RPM ranges (14 amps at approximately 1800 RPM was obtained during prolonged bench tests


PURCHASE PRICE: U.S. $250.00 each (plus shipping) and includes the following:


  1. Solid state voltage regulator and small parts kit as pictured above.
  2. Detailed installation and operation booklet, including diagrams and a troubleshooting guide.


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