Ups Features; Figure 2-7: Path Of Current Through The Ups In Bypass Mode - Eaton 93PM User And Installation Manual

NOTE
The critical load is not protected while the UPS is in Bypass mode.
Internal relay contacts

Figure 2-7: Path of current through the UPS in bypass mode

In bypass mode, the output of the system is provided with three-phase AC power directly from the
system input. While in this mode, the output of the system is not protected from voltage or frequency
fluctuations or power outages from the source. Some power line filtering and transient protection is
provided to the load but no active power conditioning or battery support is available to the output of
the system in the bypass mode of operation.
The static bypass is comprised of a solid-state, silicon-controlled rectifier (SCR) static switch (SSW)
and a backfeed protection isolation device K5. The static switch is rated as a continuous-duty device
that is used anytime the inverter is unable to support the applied load. The static switch is wired in
series with the backfeed protection. The static switch, being an electronically-controlled device, can
be turned on immediately to pick up the load from the inverter without interruption. The backfeed
protection is normally always closed, ready to support the static switch unless the bypass input
source becomes unavailable.

2.3 UPS features

The Eaton UPS has many features that provide cost-effective and consistently reliable power
protection. The feature descriptions provide a brief overview of the UPS standard features.
P-164000249 30-200 kW 17
Revision 2 User's and Installation Guide