If the input power fails to return or is not within the acceptance windows required
for normal operation, the DC/DC converter continues discharging until a DC
voltage level is 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 alarms indicating that the DC source has a minimal capacity left and a
system shutdown is imminent. Unless utility power is restored, the output can be
supported for a maximum of 2 minutes before the output of the system shuts
down. If the bypass source is available, the UPS transfers to the bypass mode
instead of shutting down.
If the input power becomes available again at any time during the discharge, K1
and K5 close and the UPS returns to normal operation. The UPS also starts to
recharge the DC source to restore the capacity.
3.3.3
Bypass mode
CAUTION
The critical load is not protected while the UPS is in bypass mode.
The UPS automatically switches to the bypass mode if it detects an overload,
load fault, or internal failure. The bypass source supplies the commercial AC
power to the load directly. The UPS can also be commanded to transfer to the
bypass mode manually through the display. The UPS status indicated on the
display is
On Bypass
.
The UPS returns from the bypass mode back to online mode, if the condition (for
example overload) that caused the transfer is cleared. If there is a condition that
does not clear by itself (for example UPS internal failure), the UPS remains on
bypass operation.
Figure 8: Path of current through the UPS in the bypass mode
shows the path of
electrical power through the UPS system when operating in the bypass mode.
© Eaton Corporation plc 2020. All rights reserved.
Revision: 001
Document ID: P-164000956
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Eaton 93PM G2 UPS 50 – 360 kVA
User’s and Installation Guide
