The ABB ATS021 is a compact automatic transfer switch (ATS) controller used in electrical power systems to manage and automate transfer between two power sources — typically a primary (normal) line and a secondary (emergency or generator) line. It continuously monitors the voltages of both power lines and, based on adjustable thresholds and delays, controls the opening and closing of associated circuit breakers to transfer loads when an anomaly (e.g., mains failure) is detected and to restore the original source when it returns. The unit supports both automatic operation and manual override and is suitable for a wide range of industrial and commercial installations requiring reliable automatic transfer performance.
