I want to know the answer to the following question:
What three elements determine the size of the air-gap area and back iron depth?
All the background I'm provided with is that "The continuous torque density of conventional electric machines is determined by the size of the air-gap area and the back-iron depth, which are determined by the power rating of the armature winding set, the speed of the machine, and the achievable air-gap flux density before core saturation.". Is that enough to answer the question?
Answer: yes