Eaton 91PS User And Installation Manual

Also see for 91PS: Safety and installation quick guide Safety and installation quick guide User and installation guide User and installation guide

Contents

Figure 5. Path of current through the UPS in the battery modeA Staticswitch1 Bypass in-putMain power flowB Rectifier 2 Rectifier in-putEnergizedC Inverter 3 Output De-energizedD Battery con-verter4 BatterybreakerTrickle currentE Battery Closed OpenDuring a utility power failure, the rectifier no longer has an AC utility source fromwhich to supply the DC output current required to support the inverter. The inputrelay K1 opens and the UPS output is powered from the batteries through theinverter. As the inverter operates uninterrupted through the transition, the loadremains supported continuously without disturbance. If the UPS static bypass issupplied from the same source as the UPS rectifier, the backfeed protectioncontactor K5 also opens. The opening of K1 and K5 prevent system voltagesfrom bleeding backwards and re-entering the input source through the staticswitch or rectifier.If the input power fails to return or is not within the acceptance windows requiredfor normal operation, the battery continues discharging until a DC voltage levelis reached where the inverter output can no longer support the connected loads.When this event occurs, the UPS issues a set of audible and visual alarmsindicating that the batteries have a minimal capacity left and a system shutdownis imminent. Unless utility power is restored, the output can be supported for aEaton 91PS/93PS UPS 8-10 kW User's and installation guide© Eaton Corporation plc 2018. All rights reserved. Revision: 003 Document ID: P-164000672 22 (102)