Comparative study of slotted and slotless electronically-commutated permanent-magnet DC servomotors

Permanent-magnet excited DC servomotors with electronic commutation are becoming increasingly attractive in many applications due to their performance advantages such as reduced size and weight, high efficiency, low noise and maintenance, improved reliability and very good control characteristics in a wide speed range. The authors compare both slotted and slotless options for electronically-commutated neodymium-magnet DC servomotors on the basis of the torque capability for the same frame size and Joule´s losses amount