Toshiba: AS3U Low Voltage Drive – Integrated Harmonic Filtering in a Single Enclosure
May 11, 2026
In water and wastewater facilities, as well as many continuous duty industrial pumping systems, power quality is not an abstract requirement. It affects motor heating, transformer loading, and the stability of backup power systems.
To address these practical constraints, the AS3U series combines an AS3 adjustable speed drive with an integrated passive harmonic filter in a UL Type 1 free‑standing enclosure. This factory‑integrated solution reduces upstream harmonic distortion while simplifying installation by eliminating the need for additional filters.
At full load, the AS3U is designed to limit total harmonic current distortion to 5 percent or less, helping support overall system compliance with IEEE 519 standards. This integrated approach also reduces wiring complexity and commissioning time compared to multi‑component solutions.
Stable Power for Critical Pumping Loads
Low harmonic current reduces electrical stress on motors, transformers, and backup power systems, supporting reliable operation in continuous duty pumping environments.
Energy‑Efficient Operation Across Load Profiles
The AS3U delivers 96 percent or greater efficiency with THDi of 7 percent or lower at loads of 50 percent and above, making it well-suited for variable flow pumping applications.
Simplified System Architecture
With the passive harmonic filter integrated at the factory, the AS3U helps eliminate external filters, related wiring, and coordination effort.
