Powerware 9170+ - Manual (Page 64)

Operation
60 Powerware ® 9170 User's Guide S LTM-1344 B Uncontrolled Copy
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
setpoints. If the input voltage or frequency deviates beyond these
setpoints, the Powerware 9170 system transfers to the Double
Conversion 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. 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.
The UPS will not automatically recover from the Sleep mode, regardless
of the state of the Auto Restart parameter.
Figure 46 shows the basic functional elements of the UPS.
Input
(Utility)
Power
Input Power (Boost)
Converter
Internal DC
Power Bus
DC/AC Power Inverter
Output Relay
Bypass Relay
Capacitor Bank
Battery Charger
Battery
Modules
(Parallel)
Line/Battery
Relay
Isolation
Transformer
(Optional)
EMI/RFI
Filter
Figure 46. Powerware 9170 UPS Functional Block Diagram