Re: Voltage Regulation, Re: 1959 Starflite

[rvpapasso]

I have never seen a 12v mechanical regulator that did not have a current limiting unit. As far as I can determine all the OMC 12v generator mechanical regulators were 3 unit with current regulating.

With regards to Harley, the answer is yes and no with regards to including a current limiter. Typically the 6V regulators were 2 unit, cutout and regulator. Because the demand on the battery was low due to lack of electric starting, the battery, if well maintained, would not get deeply discharged in normal use.

In 1965 Harley introduced 12V to run their first electric starter on the big twin. Since electric starters can discharge a battery in a short time of cranking all the 12V mechanical regulators were 3 unit to include current limiting to protect the generator since the battery after cranking is going to suck a lot of current to be replenished.

The voltage regulator sold by JP cycles is actually made by Cycle Electric, model CE 102. It is designed for the Harley model 65 generator. This is a 12V, 10A generator. Harley had a great way to identify the year parts were first introduced by including the year in the part number. The previously generator mentioned, 32E, was first introduced in 1932, 5th revision. The model 65 generator came out in 1965, same year as 12V systems were introduced for their first electric starter also introduced in 1965.

All Harley generators run faster than the crank speed due to gearing between the crank and the generator gear. The only motorcycle I can remember that had the generator running at crank speed is the 70’s Yamaha 125. The generator was mounted directly at the end of the crank. It was unique that the generator also doubled as a starter. By mounting it directly to the crank eliminated the problem of generator belts, drive gears and over run starter engagement mechanisms.

I never counted the flywheel teeth on my 1960 40Hp Johnson or the generator pulley to determine the ratio. However the generator is spun faster than the crank.

For a generators getting the RPM right for all crank speeds is an interesting science. Too slow and the generator doesn’t put out anything useful. Too fast and the magnetic field starts to warp where it only passes thru part of the armature decreasing output and causing all the current to run through less windings, I.e. Heating up the armature. This is why most generators are designed to work at high RPMs and not at low RPMs since most driving is above idle. If the ratio was changed to spin the generator fast for low RPMs then at higher RPMs the generator output would decrease or burn out the armature due to the magnetic field warping.

Alternators do not have this problem due to spinning the field instead of an armature. That is why car alternators put out useful voltage at idle and also at high RPMs. No matter how much the magnetic field warps there is always a stator coil to pick it up.

Sorry for the detour from topic.