The diodes in the alternator have withstood running at no load 105 volts so far. I suspect this bit of information from the backshed might shine some light on the matter?
A bit off topic, but a delta connection would very likely produce some nasty circulating harmonic currents, because the waveforms are not pure sine waves.
A star connection with a floating mid point solves that particular problem very neatly, which is why they do it that way.
Most of the alternator diodes I have tested will work to at least 200 volts and probably much more, even though they may be rated to only 100 volts max.
What happens is, a manufacturer builds a whole bunch of diodes and they are individually automatically non destructively avalanche tested (for breakdown voltage).
The really good ones might be rated at 600 volts, and will probably withstand much more than 600 volts. These are stamped xxx/600 (or something similar)
The next batch might avalanche between 500v and 600v, these are stamped xxx/500, and so on down to the crappiest which become xxx/100 devices.
But superb quality control in your diode factory has resulted in every diode coming off the production line testing better than say 580 volts.
But you still need to supply bulk orders of very cheap xxx/100 diodes to the alternator manufacturers.
So they just stamp as many of the good diodes as being rated at only 100 volts.
So don't be too surprised if your alternator diodes easily survive voltages way above the rated 100 volts.
__________________
Cheers, Tony.
The alternator I have is from the 1970's. Back then things were not as cheap as they are now so the unit was built to last. I am not saying something won't happen? But I have not had any problems with the diodes yet.
Robert