The second stage of the ECM motor is usually 100% peak speed as designed for CFM’s and tonnage of the system.įrom low to high speed the ECM (Electronically Commutated Motor) maintains a good efficiency range between 60% and 80% between all speeds versus the PSC motor with multiple windings getting between 10% efficiency at lower speeds to nearly 50% efficiency at higher speeds. The first stage in the program is usually a lower speed in the cooling cycle to remove humidity.Ī slower rate of an airflow across the evaporator coil allows the cold evaporator coil to remove the humidity in the air. The ECM motor (Electronically Commutated Motor) is preprogrammed to run at certain speeds as determined by the HVAC manufacturer such as Trane, York, Lennox, or Carrier. Efficiency Ranges and Other Factors for Variable Speed GE ECM Motors A big part of air conditioning is humidity removal and the variable ECM blower motor helps humidity removal when the motor is stepped up as described. The less the humidity in the air the cooler you will feel. This is important in the summertime when humidity levels are typically high in many geographical areas. The benefit of this is it can reduce humidity in the air when the unit first starts. The typical PSC motor starts and immediately goes to 100% and then stops almost immediately (aside from inertia) when the thermostat satisfies. Please use the search feature to the right to help you find other related articles. This is often referred to as soft start and soft stop. When the thermostat satisfies the motor will slowly ramp down and then stop after so many minutes. The air handler will turn on and ramp to 50% (or whatever percentage the manufacturer deems appropriate) and then after so many minutes as determined by the program the ECM blower will ramp to 100%.