As seen in "UK Work Log page#1" I have replaced the headlights for H4 Halogen units. The lights are great, much better than the GEC sealed beam units. The only downfall of using the H4 lamps is that they take more current than the GEC sealed beam units.
The power produced by the Lucas D42 dynamo and controlled by the RB310/RB106 regulator is set to 22 Amps. Now the H4 lamps have been fitted the power required is 25 Amps. By obtaining and fitting the 6GC regulator the dynamo now produces up to 30 Amps of power.
The 6GC, much older in design than the RB310/RB106 regulator, has the added advantage of a third coil. The third coil is used to control current which means that when the headlights are switched on additional current is drawn from the dynamo thus maintaining voltage level at around 13.5 volts at 30 Amps. The original fitted 2 coil regulator maintains a voltage level of 14.6 volts off load and less than 12.3 volts at 25 Amps. This means that the lights are not maintained at the proper brilliance when in use for a prolonged period because the 2 coil regulator is unable to supply enough current. The battery must supply the balance to power the headlights and will eventually drop below 11.5 volts.
Lucas
RB310/RB106 two coil MGA regulator.
Lucas
6GC three coil MGA regulator.
