11
Powerware 9315 (200 kVA---300kVA) Opera tion
164201036 Rev.D 041500
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 directly.
CAUTION:
The critical load is not protected while the UPS is in Bypass mode.
Figure 4 shows the path of electrical power through the UPS system when the UPS
is operating in Bypass mode.
Patho f electrical power
Bypass
Rectifier
K4
Input
Input
K3
CB1
(open)
BATTERY
RECTIFIER INVERTER
Output
TRANSFORMER
BYPASS
Figure 4. Path of Current Through the UPS in Bypass Mode
You can transfer the UPS from Normal mode to Bypass modemanually. However,
the UPS switches automatically to Bypass mode whenever the inverter can no
longer supply the critical load. If the U PS 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). The fourth transfer will lockthe critical load on the bypass source and
requires operator interventionto transfer.
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.