Powerware 9170 User Manual page 84

Operation
The High Efficiency (H.E.) mode is a user-programmable automatic mode
of operation. This mode allows power to flow through the internal UPS
bypass path for as long as AC input stays within the user-defined set
points. If the input voltage or frequency deviates beyond these set
points, the Powerware 9170
mode of operation. Complete loss of input voltage causes the UPS to
transfer to Battery mode. While in H.E. mode, the Powerware 9170
system provides passive EMI filtering in the power path.
Off mode turns off the output and most internal circuitry. Within this
mode, another mode (Sleep) turns off all internal circuitry when AC line
is not present and battery voltage drops to a low threshold. If AC input
voltage is not present in Off mode, the user can direct the UPS to enter
Sleep mode by selecting the Battery Protect (BP) feature (see "Removing
Input Power" on page 77). When AC input voltage returns in the Off
mode (caused by a low battery alarm condition), the UPS automatically
recovers and, if the Auto Restart parameter is enabled, switches to
Double Conversion. Auto Restart is enabled as a factory-default.
After a discharge and subsequent low-battery shutdown, the UPS will
automatically recover from Sleep mode if the Auto Restart parameter is
enabled.
Figure 53 shows the basic functional elements of the UPS.
Input
Input Power (Boost)
(Utility)
Line/Battery
Power
Relay
EMI/RFI
Filter
Battery
Modules
(Parallel)
Figure 53. Powerware 9170
76
+
system transfers to the Double Conversion
Bypass Relay
Converter
Internal DC
Power Bus
Battery Charger
Capacitor Bank
+
UPS Functional Block Diagram
Powerware 9170
®
DC/AC Power Inverter
Output Relay
+
UPS User's Guide Rev B www.powerware.com
S
+
Isolation
Transformer
(Optional)