Relative angle of magnetic fields in DC Motor I'm building my own generator. What is the ideal angle between the magnetic field of the stator in relation to the induced magnetic field of the rotor? Is there a formula to calculate it? For some reason I always went with 45 degrees, but now that I'm building a bigger machine I want to be certain.

 A: So a relevant term here is 'electrical degrees'. From this source I take this equation:
$$
\theta_\text{mech}=\frac{2}{p}\theta_\text{elec}
$$
I am not sure of the technical details of calculating the exact force between a rotor and stator system, but I do know that when operating the stator applies a torque on the rotor based on the angle between the two. A few quick searches lead me to this electrical engineering question wherein the top answer states that force will be proportional to the sine of the electrical angle between the motor and rotor.
So the rotor and stator should be 90 'electrical degrees' apart. So for a two pole motor they should be 90 mechanical degree apart. For a four pole motor, they should be 45 mechanical degrees. For a six pole motor, they should be 30 mechanical degrees apart.
In your image I count 6 windings or magnets on half the rotor, so I guess that this is a twelve pole motor, so 90 electrical degrees is 15 mechanical degrees. If it is an eight pole motor then 22.5 mechanical degrees. So it should be 15 to 30 degrees depending on your motor.
