Charging System Learning experience

[Hoople]

The thing that ALWAYS gets me about the Harley charging system seems to be it's frailty.
Take a Transformer.110kv to 11kv;33kv to 415v;11kv to 415v.Dosen't matter what size.Lots of copper windings in close contact separated by insulation and resins.Induced voltages.Works in an extremely hot,oil and air cooled environment for up to 40 odd years with NO maintenance;maybe an oil change if it's lucky.Operates at 100% efficiency and in overload conditions every day(at least ours do!)And does this for ever.With ever variable voltage and current fluctuations.

I know they're different animals,but they are SIMILIAR animals.
Harley could make superior windings if they so chose:better wire,better insulation,better resins,better and longer performance.Cost a few bucks extra and provide more reliability.

Yes they are similar but there are a few very important exceptions. I would bet that in most cases, (90%) our stators demise is caused from 1 of the 6 rectifiers shorting out in the regulator. Once that happens a strong short is placed across at least 1 of the stator phases. From that moment on, no matter what materials you used to make the stator from, it's life is going to be short lived.

When comparing the stator to power transformers the same is true. The reason why those oil filled transformers live so long is because they have cartridge fuses that explode to protect them when a tree falls on a power line. Take for example a 3 phase pole transformer. Take just one phase of it and place a load on it that exceeds it's rated capacity by 100% without any fuses to protect it. I bet in time the oil will overheat and within a short time the transformer will be toast.

I believe most (not ALL but most) stator failures are caused due to problems DOWNSTREAM from itself. There is nothing in place to protect or disconnect the stator from an unusual load that is downstream from itself. (i.e. shorted rectifier, shorted cell etc)

 

[91FXRS-Conv]

The primary difference between a line transformer and a Harley system is that there is no rectifying happening in a utility system. They also have no weight restrictions, so they can use a lot of copper.

I'm real skeptical that diodes in the regulator can "short", in all my years of working on alternators of all kinds, that is really, really unusual. Diodes fry, then conduct nothing, either way, in every other application I've seen. That increases the loads on the other diodes as they have to pass more current to maintain charge, which takes them out sooner.