Abstract: A circuit arrangement for judging the lifetime of a battery used in a no-break power supply system includes a step-down transformer connected to an AC power source, a first switch connected between the transformer and a rectifier, a voltage detector connected to one electrode of a battery, an auto-timer connected to the voltage detector, and a second switch connected to the auto-timer and interlocked to the first switch.

Abstract: A no-break power supply system for use in a computer power supply source is disclosed. The system comprises a switch connected to a main or commerical power supply source and having first and second contacts, a first rectifier means connected to the switch through an overcurrent breaker, an inverter connected to the first rectifier means for supplying an output with constant voltage and constant frequency to a load, an emergency generator means connected to the switch for generating a supply voltage in the case of service interruption or failure of components, a second rectifier means connected in parallel with a series combination of the switch, the overcurrent breaker and the first rectifier, and a voltage relay means connected between the emergency generator means and the emergency battery means and for triggering the emergency generator means.