16
1600XP Series Installation and Operation Manual
10. Operating Modes
10.1 Static-Bypass (Stop operation)
If the UPS unit is severely overloaded or develops an internal fault, power ow is automatically switched
from the unit’s main circuit to the bypass circuit. Power ow through the bypass is shown in the following
illustration. This change-over occurs automatically in phase in less than one-quarter cycle of the input
waveform. The switching period is not long enough to cause interruptions to occur in most loads.
• If the power ow is transferred to the bypass circuit due to an internal fault the UPS will continue to
supply power to the load through the bypass and indicate a system fault message (see system fault
messages on pages 47–48).
• If the power ow is transferred to the bypass circuit due to an overload condition (see system warning
messages on pages 48–49), then the power ow will automatically transfer from the UPS’s bypass
circuit back to the inverter circuit after removing the overload if set to do so (AutoXfer parameter (Cmd
ID 660)).
10.2 On-Line (Run operation)
The following illustration shows circuit power ow when the UPS is operating normally in the On-Line
mode. The UPS rectier, including a boost chopper circuit, converts AC input power to DC power. The
boost chopper circuit maintains a constant voltage, with current limiting, for charging the batteries.
The inverter section generates a high quality sinusoidal output voltage. The unit’s batteries are always
maintained in a constantly charged state when the UPS is in the run operation mode.
Output
Power
Line Filter Inverter
*Static Switch
Isolation
Transformer
Input
Power
Input
Fuse
Power Flow
Bypass
* Switches are
solid state
devices.
MCCB
Output
Fuse
Surge
Absorber
Batteries
+
–
Rectier/
Chopper
POWER FLOW IN ON-LINE MODE FOR ALL MODELS
Negative Bus
POWER FLOW IN BYPASS FOR ALL MODELS
Output
Power
Line Filter Inverter
*Static Switch
Isolation
Transformer
Input
Power
Input
Fuse
Power Flow
Bypass
* Switches are
solid state
devices.
MCCB
Output
Fuse
Surge
Absorber
Batteries
+
–
Rectier/
Chopper
Negative Bus
