Drive selection memo — HVAC packaged drive with bypass
The ABB 3AUD0000003728 is a factory-packaged HVAC drive combining an ACH580 variable-frequency drive with an e-clipse bypass and a circuit breaker disconnect in a single NEMA Type12 enclosure rated IP55. This is the UL-listed variant: light-overload duty at 350 Hp, 414 A output, fed from 440–480 V three-phase at 50/60 Hz. The bypass means the motor can run across-the-line if the drive faults or needs service — a standard requirement for critical HVAC fans and pumps where maintaining airflow or circulation takes priority over variable-speed savings.
The 414 A light-overload (UL) rating is the continuous output current the drive can deliver without exceeding its thermal limits under typical HVAC variable-torque loads — fans, centrifugal pumps, compressors. That 350 Hp figure at 480 V tells you the maximum standard motor frame it can drive in UL service. The 440–480 V input range covers 460 V and 480 V nominal systems common in North American industrial and commercial panels; the 50/60 Hz acceptance means it works on either line frequency without derating. The NEMA Type12 enclosure (IP55) keeps dust, falling dirt, and hose-directed water out — suitable for indoor equipment rooms, rooftop installations under a shelter, or washdown-adjacent areas where the drive isn't directly sprayed but sees condensation and airborne particulates.