Stator blows with annoying regularity? then read this

[George R. Young]

The approximation part:

At 10000 RPM, the open circuit voltage is 100 VAC, the impedance of the windings is 5 ohms, and it's working into a load of 14 volts.
Current = (100 - 14)/5 =17.2A

At 5000 RPM, open circuit voltage is 50 VAC, the impedance is 2.5 ohms, still working into a 14 volt load.
Current = (50 - 14)/2.5 = 14.4A

At 3500 RPM, open circuit voltage is 35 VAC, the impedance is 1.75 ohms, still working into 14 volts.
Current = (35 - 14)/1.75 = 12 A

It's obviously not exactly constant, but it doesn't vary much with RPM.

[motoracer8]

There is a good artical about a better regulator on eviltwinsbk.com it's even a Yamaha part. Check it out.

  Ken G.

[jasonm.]

George.DC volts is the result of the R/R after the AC from the stator. Which was never in question. ..

you say "not vary much". You just stated the AC voltage changes with RPMs clearly 10vac/ 1000rpm. This is what I am saying. RPM = voltage AC. The issue is wasted AC causing heat.  AND thank you for your observations.

[fret not]

That Evil Twins discussion is really good.  So much to learn, so little time . . . . . . .  :)

[George R. Young]

. . . snippety . . . you say "not vary much". You just stated the AC voltage changes with RPMs clearly 10vac/ 1000rpm. This is what I am saying. RPM = voltage AC. The issue is wasted AC causing heat.  AND thank you for your observations.

Not one to give up:

When the RPM rises 300% (from 3500 to 10000) the current rises only 50% (12A to 17A), that's what I mean by 'not very much'.

The heating of the wires is caused by the current (that 12 - 17 A figure) and the resistance of the windings, which is constant. The current also flows through the inductive component of the impedance (i.e. the part that varies with RPM), but this causes no heating.

The fact that both the open-circuit voltage and the impedance vary with RPM is not relevant to heating the wires, except that it causes the current to be 'approximately constant'.