Classic/Antique Car Repair: electronic voltage regulator, electronic voltage regulator, electronic regulators

Question
I have an old car (1937 Bentley) with a negative ground electrical
system.  The car originally had a Lucas three pot voltage
regulator/current regulator, and a two brush generator.  The
generator works fine, the voltage regulator was replaced at one
time with a CAV three pot system. The hookup is similar to that
used with the Lucas RB 106 type used on many mid-fifties and
sixties British cars.  I would like to replace the  CAV one with a
small, modern, reliable electronic regulator.  Many of the
modern electronic regulators only have three connections. How
should the ignition warning light be hooked up?  Is a current
regulator or cutout typically included? Any recommendations?

Thanks for the help.

Answer
Hi Philip,
I have very little Bentley experience but am suprised to hear that a 37 Bentley had a negative ground, or was it conveted? The Ign. light was a charge light on most all British cars. If you are using a DC generator that is negative ground or polerized to work as a negative ground and you have found a solid state regulator then you would look at the connection directions with the new reg for a "charge light" connection or an "Ign On" connection to apply the Ign light outlet to. If you have a two post generator then the smaller of the two terminals is the field and the regulator applies power to the field to vary the output. If there is no connection on the new reg for a charge light, first try using the Ign light output as the Ign. on power for the reg. If that don't work put a voltmeter across the battery and connect the output of the Ign light to the field terminal and check the operation, Ign ON = light ON. Engine at a fast idle should = light off.
Let me know by e-mail  longez8@bellsouth.net
Howard