Good to see this thread started Grum.
First up,i hope ION joins us here,as we once and for all answer this question correctly,by way of accurate testing.
My thought toward this experiment is a simple setup,where we measure temperature differences between different setups of the DUT.
I believe that if i were to make a sealed box for the DUT to be placed in,and then measure maximum achieved temperature within that box of the various setups of the DUT,then we could get a clear indication as to whether or not the PMs were responsible for any temperature increase.
I would need to build a base to carry a wound rotor and brush assembly--timber would probably be best.
We would also need to be able to change out steel laminated stator blocks for PMs easily.
P/in would have to be limited,by both way of the power supply,and a breaking system on the rotor to keep the RPM at a set range. This is where i can kill two birds with one stone,in that i can use my eddy current heat generator as a eddy current break to maintain the same RPM throughout the testing.-->one would think that if the RPM is the same,then the current draw would also be the same,but that is not the case,as i found out with previous testing in another experiment,as there will be very little BackEMF produced by steel laminated blocks as stator blocks. So instead of using steel laminated blocks for the stator,i will use weak ceramic magnets to start with. Once we have gained our maximum heat within the sealed box,i will then change out the ceramic magnets for strong neo's,and carry out the test once again. After all the numbers are in,we then have to place a good size resistor in the box,and deliver the same amount of power to that resistor as we delivered to the motor. If the resistor cannot produce the same amount of heat within the box,we then must go to plan B (which i dont have yet),and carry out a varifying test.
To me,the PMs do work in a DC motor,as every action has an equal and opposite reaction,and so if the action is doing work,then it must be true that the reaction is also doing work.
Some may say-but the PMs are stationary,and so no work is done. But what then with an outrunner motor,where the rotor is the PM,and the stator that is stationary are your windings--the PM now has motion,and so must be doing work.
It is my thought that when i replace the weak ceramic magnets with stronger neo's,even at the same RPM,the current draw will drop on the DUT,due to the stronger magnets creating a larger BackEMF--would this not be work being done ?,decreasing power to the motor,but increasing mechanical output power-->what did that,if nothing else changed?-->but this is just a guess ATM,and actual outcomes can only be had by way of experimentation.