I put this under hydro because that is the application.
Photo of the rotor:
http://johansense.com/bulk/synchronous_mod7.JPGI will replace that photo with an updated shot, i added two more coils to it.
I got rather lucky with rather low cogging, but it could have used a bit more math (i didn't do any) to find the optimum location for coil placement.
In any case the voltages and current you see in that chart correspond to WYE line to line voltage across a single 240 volt winding.
The frequency is 14.91Hz as the machine is driven by an 8 pole induction motor.
So multiply the voltage in that chart by 4 to find nominal 3600 rpm voltage.
I'm actually quite impressed that the saturation point seems to be nominal "rated" volts per hz.
some background on the motor:
It is a marathon 2 hp 3450 rpm 3 phase 240/480 volt 1.15 service factor.
The winding stack is 3.00 inches high, the diameter of the rotor is 3.000 inches, and there is about .75 inches of "back iron" behind the 24 slot winding.
It is wound with 20 gauge wire and IIRC 1.8 ohms per winding. so that's 3.6 phase to phase for wye, and a single 240 volt segment.
480 volt wye would be 7.2 ohms phase to phase, 240wye is 1.8 ohms
7.2 ohms comes out to about 420-440 turns, so that makes about 244 mm^2 copper per phase.
this means the peak flux at 240/480 volts is about 1.3-1.35T, which is the nominal knee for cheap E core transformer steel as well.
The winding arrangement is the worst possible.
If you go here:
https://www.emetor.com/edit/windings/select 2 poles, 24 slots and the worst possible winding arrangement, the nominal winding factor is .83, and click on show winding layout and you will see how its done.
The rotor's main coil is 37 ohms of 26 awg wire and that's about 742 feet and that's about the number of turns. the two lesser coils are at about 150 electrical degrees (i think) and are both 10 ohms, so the total is 57 turns.. works out to about 1200 turns.
1200 turns is about 181 mm^2 of copper.
now that I've thought about this it makes sense to unwind the tertiary coils and mill the slots wider.. but its not worth the effort.
the main coil could also be milled wider as well, as i only have 75% of the copper area of the stator, on the rotor.
but at "nominal" volts per hz is .701 amps on the stator, that is 28 watts lost for magnetization.
so that's 5.1 amps per mm^2.
I don't know the relationship between stability angle and additional stator amps but i think its simple to see that at 1 amp of rotor current we have a surplus of about 400 amp turns to drive the stator coils..
which works out to about one amp at 480 volts/60hz.
480 volts, 480 watts
57 lost in the rotor
20? lost in the stator iron
7.2 lost in the stator copper
bearings? windage?
Probably on the order of 80% efficiency, at 3600 rpm and 480 volt output.