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5.2
Single UPS
A single
conditioned and uninterruptible AC power to the critical load from the output of the module. During
an outage, the inverter continues to operate, supporting power to the load from the battery supply. If
the unit requires service, applied loads are transferred to the internal bypass either automatically or
manually. With the exception of an optional external battery cabinet, no other cabinets or equipment are
required for the single UPS to successfully support its applied loads.
5.2.1
The Eaton 93E MK2 UPS supports a critical load in four different modes of operation:
•
In Standard Normal mode, the critical load is supplied by the inverter, which derives its power from
rectified utility AC power. In this mode, the battery charger also provides charging current for the
battery, if needed, Standard mode is the standard normal operating mode.
•
In High-Efficiency (HE) mode, commercial AC power is supplied directly to the critical load
through the internal bypass and transfers automatically to Standard Normal mode (double-
conversion on demand) if an abnormal condition is detected.
•
In Bypass mode, the critical load is directly supported by utility power.
•
In Battery mode, the battery provides DC power, which maintains inverter operation. The battery
supports the critical load.
The following paragraphs describe the differences in the UPS operating modes, using block diagrams to
show the power flow during each mode of operation.
5.2.2 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,
overvoltage, under voltage, 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.
5.2.3
During Standard Normal mode, power for the system is derived from a utility input source through the
rectifier input contactor. Three-phase AC input power is converted to DC using IGBT devices to produce
a regulated DC voltage to the inverter. When the battery contactor is closed the battery is charged
directly from the regulated rectifier output through a buck or boost DC converter, depending on the
system voltage and the size of the battery string attached to the unit.
Figure 5-2 shows the path of electrical power through the UPS system when the UPS is operating in
Normal mode.
The battery converter derives its input from the regulated DC output of the rectifier and provides either
a boosted or bucked regulated DC voltage charge current to the battery. The battery is always
connected to the UPS and ready to support the inverter should the utility input become unavailable.
The inverter produces a three-phase AC output to a customer's load without the use of a transformer.
The inverter derives regulated DC from the rectifier and uses IGBT devices and pulse-width
modulation (PWM) to produce a regulated and filtered AC output. The AC output of the inverter is
delivered to the system output through the output contactor.
41
Eaton 93E MK2 UPS (10-40kVA, 380/400/415V) Installation and Operation
UPS operates independently to support an applied
Modes
Note：Need to enable HE mode from LCD
Standard Normal Mode
load from the
inverter, providing
blackout,
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