Which feature is characteristic of an Electrically Commutated Motor (ECM)?

Electrically Commutated Motors (ECMs) are designed with variable-speed capability, allowing them to adjust their speed based on the demand from the system. This feature enhances efficiency, as the motor can optimize its performance to match the requirements of the application, resulting in energy savings and improved comfort levels. Variable-speed operation is particularly beneficial in HVAC applications, where maintaining precise airflow and temperature control is crucial.

By being able to operate at different speeds, ECMs minimize energy waste and reduce wear and tear, thus extending their lifespan. In contrast, motors that only have fixed-speed capabilities operate at a constant speed, often leading to less efficiency and higher energy usage. The other choices do not represent the defining characteristic of ECMs in the same way that variable-speed capability does; for example, ECMs typically have lower power consumption compared to traditional motors, and their design inherently offers low maintenance due to the lack of mechanical commutation components such as brushes.