Bypass Mode; Figure 19. Path Of Current Through The Ups In Bypass Mode - Powerware 5075 kVA Installation & Operation Manual

Bypass Mode

The UPS automatically switches to Bypass mode if it detects an overload, load
fault, or internal failure. The bypass source supplies the commercial AC power to
the load through an internal switch and an internal transformer.
CAUTION:
The critical load is not protected while the UPS is in Bypass mode.
Figure 19 shows the path of electrical power through the UPS system when the UPS
is operating in Bypass mode.
CB1
Rectifier
Input
Input
Isolation
Transformer
You can transfer the UPS from Normal mode to Bypass mode manually. However,
the UPS switches automatically to Bypass mode whenever the inverter can no
longer supply the critical load. If the UPS transfers to Bypass mode from Normal
mode due to any reason other than operator intervention, the UPS automatically
attempts to transfer back to Normal mode (up to three times within a 10-minute
period).
Bypass mode is a normal operating mode, and not an alarm condition. However, if
the UPS is unable to return to Normal mode following an automatic transfer to
Bypass mode, an alarm condition will be recorded.
42
BYPASS
K4
RECTIFIER
CB2
(closed)
BATTERY

Figure 19. Path of Current Through the UPS in Bypass Mode

Powerware BPIII Harsh Environment UPS 50--75 kV Installation and Operation
TRANSFORMER
INVERTER
K3
(closed)
DC/DC
CONVERTER
Bypass
Input
(BIB)
(closed)
(MBP)
(open)
OUTPUT
Output
(MIS)
(closed)
Path of electrical power
164291261 Rev. F 111503