The La Marche A-Series UPS System (AUPS) is an Uninterruptible Power Supply system designed to power critical AC loads. Modular in concept, it utilizes separate rectifier and inverter components allowing for simplicity in sizing and growth for various requirements. The Inverter section is compact and supplies a sine wave output. It provides reliability through transistor switching and a ferroresonant transformer which has inherent voltage regulation, output filtering and overload protection. The Rectifier (Charger) section uses controlled ferroresonant technology, with separate adjustable voltage settings for float and equalize. It provides high efficiency, high power factor, short circuit protection, and an integral alarm package.