Historically, the two predominant motor types have been permanent split capacitor (PSC) single-speed motors and 2.3 electronically commutated motors (ECMs) with variable-speed capability. This article looks at and compares the benefits of constant torque motor technology.

Historically, the two predominant motor types in the HVAC industry have been permanent split capacitor (PSC) single-speed motors and 2.3 electronically commutated motors (ECMs) with variable-speed capability. A third motor type, constant torque motor technology, is quickly becoming popular.