Rotary Uninterruptible Power Supply (RUPS) modules are technologically complex. Calculating arc flash hazard on systems containing this equipment requires special attention to the RUPS controls. Otherwise, the arc flash calculations could result in erroneously high values.
An arc flash hazard is a dangerous condition associated with the release of energy caused by an electric arc. To evaluate the arc flash hazard and to determine the personal protective equipment (PPE) necessary to enter the arc flash hazard zone, the engineer performs calculations to determine the incident energy buildup. RUPS modules contribute to upstream faults due to the synchronous motor/generator and flywheel, so their contribution should be included in the incident energy calculation.