Marathon Electric Motors

DC Motors / Electronically Commutated Motors (ECM)

DC motors and Electronically Commutated Motors (ECM) are both types of electric motors, but they have some differences in their construction and operation.

1. DC Motors:
• DC motors run on direct current (DC) electricity.

• They consist of a rotor (the rotating part) and a stator (the stationary part).
• The rotor contains coils or magnets, and the stator has field windings or permanent magnets. • In traditional DC motors, commutation (switching the direction of current flow in the windings to maintain rotation) is achieved using brushes and a commutator.
• DC motors are widely used in applications such as electric vehicles, robotics, and industrial machinery.

2. Electronically Commutated Motors (ECM):
• ECMs are a type of brushless DC motor.
• They use electronic circuitry to control the commutation instead of brushes and a commutator.
• The rotor typically contains permanent magnets, and the stator has windings.
• ECMs offer several advantages over traditional brushed DC motors, including higher efficiency, longer lifespan, and lower maintenance requirements.
• They are commonly used in HVAC systems, refrigeration, fans, and other applications where variable speed and energy efficiency are important.
While both DC motors and ECMs are types of electric motors, ECMs are a more advanced type that use electronic commutation to improve efficiency and performance compared to traditional brushed DC motors.

Current Applications for DC/ECM Motors

• Residential Air Conditioning – Split & Window
• Commercial Air Conditioning – Ductless, Ducted, VRF, VRV, Packaged, Centralized – Ductless, Ducted, VRF, VRV, Packaged, Centralized
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.