View Single Post
Old 11-15-2012, 05:35 AM   #31
Bill Harris
Confirmed Curmudgeon
Bill Harris's Avatar
Joined: Sep 2008
Location: backwoods Alabama
Oddometer: 7,487
Originally Posted by MotoKaw View Post
It sounds like the Omega's parallel circuit will at least bypass/moot the consequence of a bad idiot bulb circuit, and might even mask the symptom itself with higher output at lower rpm's (i.e., never triggering the light, even at idle, even with a good bulb circuit - I don't know, maybe Bill Harris can comment).
The Alternator Light bulb only comes into play when the engine is first started and provides the initial excitation of the rotor. Otherwise it's just along for the ride and sometimes provides fault diagnosis for the rotor and/or diode board. The bulb leads an easy life and rarely goes out (though I make it a point to carry a spare in the headlight shell). As an initial exciter, it's not even 100% necessary since the residual magnetism in the rotor could provide the intial excitation (but that's iffy). The Omega "parallel circuit" is simply a 330 ohm, 1/2W resistor placed in parallel with the Alternator light bulb. It's an old, old trick, been used for years. This way if the bulb expires there will still be excitation.

Nothing will prevent bad wires and bad connections. Nothing, of course, except the vigilance of the owner...

'73 R60/5 Toaster
Luddite. Not just a philosophy, a way of life...
Bill Harris is offline   Reply With Quote