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. Despite the high coercivity of neodymium or samarium-cobalt PMs, continuous torque density is virtually the same amongst electric machines with optimally designed armature winding sets. Continuous torque density relates to method of cooling and permissible period of operation before destruction by overheating of windings or PM damage. COUNT 4
QSN1 What determines continuous torque density? ANS1 size of the air-gap area and the back-iron depth QSN2 What three elements determine the size of the air-gap area and back iron depth? ANS2 power rating of the armature winding set, the speed of the machine, and the achievable air-gap flux density before core saturation QSN3 What does continuous torque density refer to? ANS3 method of cooling and permissible period of operation before destruction by overheating QSN4 How does continuous torque density vary between well designed motors? ANS4 virtually the same