Eaton Power Xpert 9395C Installation And Operation Manual

90 Eaton Power Xpert 9395C UPS Installation and Operation Manual 164000821—Rev 0666..22..44 BByyppaassss MMooddeeThe UPS automatically switches to Bypass mode if it detects an overload, load fault, or internal failure. The UPScan also be transferred from Normal mode to Bypass mode manually. The bypass source supplies thecommercial AC power to the load directly. Figure 55 shows the path of electrical power through the UPSsystem when operating in Bypass mode.In Bypass mode, the output of the system is provided with three-phase AC power directly from the systeminput. While in this mode, the output of the system is not protected from voltage or frequency fluctuations orpower outages from the source. Some power line filtering and spike protection is provided to the load but noactive power conditioning or battery support is available to the output of the system in the Bypass mode ofoperation.The internal bypass is comprised of a SCR continuous static switch. The static switch is used instantaneouslyanytime the inverter is unable to support the applied load. The continuous static switch is wired in series withthe customer supplied Bypass Breaker with Shunt trip and together they are wired in parallel with the rectifierand inverter.The critical load is not protected from voltage or frequency fluctuations or power outages while the UPS is inBypass mode.Les charges critiques ne sont pas protégées des fluctuations de tension ou de fréquence ni des pannes decourant lorsque l’onduleur est en mode Contournement.The Eaton 9395C UPS provides backfeed detection and protection through a shunt trip mechanism of thebypass input breaker.Figure 55. Path of Current Through the UPS in Bypass ModeStaticSwitchretrevnIreifitceRBatteryConverterBatteryBatteryBreakerMain Power FlowTrickle CurrentEnergizedDe-EnergizedBypass InputRectifierInput OutputClosedOpenBreakers ContactorsK1Understanding UPS Operation