Yaskawa Industrial New and Original AC Servo Motor 11.7N.m 1500r/min SGMG-20ASRAB

The box was operated with the original shaded pole motors to establish baseline data for comparison. Then the shaded pole motors were replaced with ECMs, while retaining the original fan blades.

Measurements of the following were made for comparative purposes: fan rotational speed using an electronic stroboscope, air flow using a vane anemometer, evaporator discharge air temperature along with box temperature, and voltage, current, power, and cumulative energy data at 15 minute intervals. The data speaks for itself. There is a 67 per cent reduction in power consumption of the evaporator fans alone. The testing indicated that for every two watts of evaporator fan motor power reduction experienced, a corresponding one watt of condensing unit power reduction would be experienced.

While the more sophisticated ECMs carry a higher price tag than shaded pole or PSC motors, there is a great opportunity to reduce electrical consumption. Payback is in the 18-month range but one would logically expect that the price will come down as their usage becomes more widespread.