High-Efficiency Mode; Figure 5-2. Path Of Current Through The Ups In Standard Normal Mode - Eaton 93E UPS Installation And Operation Manual

Bypass Switch (Optional Dual Input)
Bypass Input
Rectifier
Input Switch
Input
Input
Relay
Switch Relay

Figure 5-2. Path of Current Through the UPS in standard Normal Mode

If the UPS becomes overloaded or unavailable, the UPS switches to Bypass mode. The UPS automatically
returns to Normal mode when the overload condition is cleared and system operation is restored within
specified limits.
If the UPS suffers an internal failure, it switches automatically to Bypass mode and remains in that mode until
the failure is corrected and the UPS is back in service.
5.2.3

High-Efficiency Mode

When the UPS is operating in HE mode, commercial AC power is supplied directly to the critical load through the
internal bypass with the power module in a standby state. If a commercial power brownout, blackout, overvoltage,
undervoltage, or out-of-tolerance frequency condition occurs the system forward transfers to normal mode
(double-conversion on demand) or battery mode. When the input line returns to normal operating range, the UPS
returns to HE operation. For charging batteries in HE mode, the UPS will revert to normal mode to charge the
batteries, then return to HE mode when charge cycle is complete.
HE mode, if selected, is a normal operating mode, and not an alarm condition. While the UPS is in this mode,
the NORMAL light on the front display will illuminate.
Static
Switch
Rectifier
Battery
Converter
Battery
Relay
Closed
Open
Battery
Eaton 93E UPS (15-80 kVA, 380/400/415V) Installation and Operation Manual
Understanding UPS Operation
Inverter
Output
Relay
Main Power Flow
Trickle Current
Energised
De-Energised
Output
5-3