ECPM Motors maximize efficiency in variable-speed applications.

Offering 3 and 5 hp versions of both 2,400 rpm (3,600 rpm max) and 1,800 rpm models (2,700 rpm max), Gen2.0 PremiumPlus+™ Electronically Commutated Permanent Magnet (ECPM) motors utilize ferrite magnets in flux-focusing design. Motor-only rated point efficiencies are

[source: http://news.thomasnet.com/fullstory/ECPM-Motors-maximize-efficiency-in-variable-speed-applications-20001791]