I have never really been involved with VFD systems, as I have been mainly servo focused. I see that there are now motors (fairly large motors) that are perm magnet design and targeted to replace AC Sync motors in a VFD application. Their claim to fame seems to be efficiency (maybe size too). Just curious if anyone has any experiences or opinions on this.

Thank you
Tom

Permanent magnet motor also require VFD for speed regulation. But its right that the efficiency of PMM is high.

The main benefits I've seen so far from PM motors is size, efficiency and torque production at low speeds. As I understand it, the prices are also starting to come down a bit with some manufacturers focusing on creating a "standard" PM offering to bring the benefits to everyday applications.

Thank you for the info, I suppose I have just never been involved in these types of applications. I had always just lumped them into the same "low cost" VFD bucket. But with so much talk about efficiency these days, and the cost to run large motors continuously, maybe there is a growing need for the PM motors.

I've seen more of them used for high speed applications or things like wind turbines. It's not unusual to see higher pole counts, higher nominal frequency, "odd" nominal speeds and the like, but for typical applications, less complex control methods are required. Because of this, Vacon has added PM algorithms in our micro drive family, VACON 20, our current generation variable torque drives, VACON 100 FLOW and VACON 100 HVAC as well as our current generation constant torque drive, the VACON 100. We fully expect to see more PM motors in the not so distant future as the prices continue to come down.