Positive Temperature Coefficient (PTC) - A thermally reactive device which becomes highly resistive at a specific temperature or current.
Redundancy (active) - Parallel UPS configuration in which several UPS units with equal outputs are parallel connected and share the load. In the event one UPS unit fails, the other units pick up its share without any interruption in the supply of power to the load. (back)
Constant Power Discharge - A battery discharge regime whereby the current during the discharge increases as the battery voltage decreases.
Voltage Delay - Time delay for a battery to deliver the required operating voltage after it is placed under load.
Backup time - Time during which the UPS can supply the rated load with nominal-quality power while the mains are down. This time depends on the battery and the efficiency of the UPS. Typical backup ranges from five minutes to several hours.
Safety Vent - A venting mechanism designed into a cell which activates under specific conditions of abuse to relieve internal pressure.
Power Sag - Voltage below 80% to 85% of rated RMS voltage for one or more cycles.