It s a matter of design philosophy and concern for energy usage. A gear motor multiplies output torque, allows lower output speeds, and reduces load inertia reflected on the motor. It goes hand in hand with concerns for energy usage and efficient transmission of power. At Rockwell Automation, the present top size is 5 hp. This is a crossover point where heating effects become a substantial design problem.
Few exceptions exist.
These IMDs range up to 22 kW and include field-oriented and vector control models. Of course, larger power ratings will come as engineers meet design and cost challenges. Above a certain point, however, physical size of hardware makes integration of motors and drives lose all meaning. The more immediate challenge for integrated motor-drive technology is to pare down initial costs and more clearly promote product benefits to potential users. For IMDs to be a real alternative to traditional motor and drive installations in substantial numbers, some manufacturers need to take a stronger proactive stance no easy task when it means competing with alternative in-house products.