Variable Speed ECM motors

Unlike a conventional induction motor, GE’s ECM™ motor regulates itself by automatically changing its torque and speed to maintain a preprogrammed level of constant airflow over a wide range of external static pressures and does so without the use of airflow sensors.

The ECM also has implications for comfort. First, in cooling mode, an ECM equipped HVAC system
can be designed to extract more moisture from the air by slowing the airflow over the air- conditioning coil. Doing so allows the coil to remove up to six times more moisture than an unregulated system.

For optimum heating the ECM system can be programmed to deliver just the right level of airflow for
optimum low and high stage heating comfort.

The ECM can, under normal operating conditions, ensure constant comfort for the homeowner because the motor will automatically maintain its programmed level of airflow even if there are dynamic
changes in static pressure (e.g. a loaded air filter, zoning changes, obstructed supply register).

This constant airflow capability provides a number of important benefits. The ECM system can compensate for poor duct design. Systems with inadequate duct volume or abnormally high static pressure owing to the use of flex, for example, can now deliver factory calibrated airflow. The ECM system can automatically compensate for the increased static pressure as the system air filter gets“dirty”.

Better indoor-air quality (IAC) can be achieved quietly and inexpensively with the ECM motor because it can be set to run continuously at reduced airflow levels, between heating or cooling cycles. This allows the air to be filtered without excessive drafts and without sacrificing efficiency.

Many people opt to run their blower motor in between heating or cooling cycles,which is referred to as constant-fan mode. In this mode, the GE ECM™ variable-speed motor provides substantial energy savings. Unlike a conventional motor, the GE motor will typically use only about 75 watts of power compared to a conventional blower motor that uses about 400 watts. So over the course of a year, you could save about $289 (@ 10¢/kWh) on your electric bill with the GE motor.