Operation

Input

(Utility) Power

EMI/RFI

Filter

Battery

Modules

(Parallel)

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.

 

Bypass Relay

 

 

 

 

Input Power (Boost)

 

 

Isolation

 

 

DC/AC Power Inverter

Transformer

Line/Battery

Converter

Internal DC

(Optional)

Relay

 

 

 

 

Power Bus

 

 

 

 

 

 

 

 

 

 

Output Relay

Battery Charger

Capacitor Bank

 

Figure 46. Powerware 9170 UPS Functional Block Diagram

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Powerware® 9170 User's Guide ￿ LTM-1344 B Uncontrolled Copy