Assembly for an uninterrupted power supply

A rectifier (1) has a rectifier input and a rectifier output, an energy store (2) stores electrical energy, and an inverter (3) has an inverter input and an inverter output. The rectifier input is connected to a supply grid (AC1). The energy store is connected to rectifier output and to inverter input. A network (AC3) to-be-protected or a load to-be-protected is connected to inverter output of inverter. Several sensors (10) which measure voltages and/or currents have sensor output connected to controllers (5,6), for converting a parameter to-be-measured into low-voltage signal.