Electronically Commutated Motors (ECM)

ECM technology was introduced to the residential and light commercial HVAC industry in 1987 when GE®* introduced a constant airflow “variable speed” indoor blower motor. Today, ECMs are found in outdoor condenser fan and indoor blower applications in residential and light commercial HVAC systems.

These direct drive Fractional Horsepower (FHP) motors include constant torque, constant speed and constant airflow. ECMs are the most efficient FHP motor in the market and are built with an electronic control module and motor and do not use capacitors.

ECMs are categorized into the following three types:

 

Constant Airflow ECMs

Constant Airflow ECMs (also referred to as Variable Speed ECMs) are primarily used for indoor blower motor applications. They are designed with separate line voltage and communication inputs (no speed taps) and are commonly designed with 16-pin or 4-pin communication inputs. Constant Airflow ECMs are programmed by the HVAC system manufacturer. Constant airflow ECMs were introduced to the HVAC industry to provide energy savings and support system capacity related to their ability to maintain airflow when TESP (total external static pressure) increases.

Click here if you’re looking for a constant airflow ECM replacement motor.

 

Constant Torque ECMs

Constant Torque ECMs are also primarily used for indoor blower motor applications. However, constant torque ECMs are designed with separate line voltage inputs and low voltage speed taps. They are commonly designed with 5 speed taps and are also programmed by the HVAC system manufacturer. Constant torque ECMs were introduced to the HVAC industry primarily to provide energy savings. This is evident in their adoption into HVAC systems with the 13 SEER energy regulation in 2006 and the FER energy regulation in 2019.

Click here if you’re looking for a constant torque ECM replacement motor.

 

Constant Speed ECMs

Constant Speed ECMs are primarily used for outdoor condenser fan motor applications. They are designed with separate line voltage inputs and low voltage speed taps or communication. Constant Speed ECMs are commonly designed with leads out instead of plug connections for weather protection. They are also programmed by the HVAC system manufacturer.

If you’re looking for a constant speed ECM replacement motor, contact the manufacturer of the HVAC system from which it was removed.

ECMs are complex, microprocessor-driven motors that incorporate electronic controls with a mechanical motor. However, from a user point of view, these motors are not that difficult to operate, adjust or diagnose, if you know what they require to operate properly. In fact, these motors can help reduce on-truck inventory, allowing you to complete more calls on the same day without driving to retrieve a part.