This paper provides an overview of the electronically commutated motor (ECM), specifically as it applies to an application in an air terminal unit. Comparisons of efficiencies for an ECM and traditional permanent split capacitor (PSC) motor are presented, as well as a novel relationship for the determination of a system’s downstream static pressure when an ECM motor’s rpm and flow rate are known. In this investigation, the ECM motor consumed less power than the PSC motor for all points examined. The cost difference for operating the ECM motor ranged from about 30% lower during high flow rate conditions to about 70% lower during turndown.

Units: Dual