Electromagnets for the rotor cause significantly more heating, exactly where it is hardest cool, and where the heat is most likely to seep into the load.
For high torque density applications, heat dissipation is often the limiting factor on duty cycle.
Also, the slip rings capable of passing high current to an electromagnet rotor are expensive and less robust than permanent magnets.
Essentially: it’s possible but I haven’t seen an application where it’s practical.
For high torque density applications, heat dissipation is often the limiting factor on duty cycle.
Also, the slip rings capable of passing high current to an electromagnet rotor are expensive and less robust than permanent magnets.
Essentially: it’s possible but I haven’t seen an application where it’s practical.