Understanding UPS Operation
If utility power is interrupted or falls outside the parameters specified in Chapter 15, “Product Specifications,” the UPS uses a backup battery supply to maintain power to the critical load for a specified period of time or until the utility power returns. For extended power outages, the UPS allows you to either transfer to an alternative power system (such as a generator) or shut down your critical load in an orderly manner.
The emergency bypass consists of a
The operation of the UPS system is described in greater detail in the following paragraphs.
The UPS module may be configured for standalone, single module, Reverse Transfer (RT) operation or multiple module, parallel redundant and/or parallel capacity operation (see paragraphs 7.2 and 7.3).
7.2 Single Module Reverse Transfer (RT)
A single module operates independently to support an applied load from the inverter, providing conditioned and uninterruptible AC power to the critical load from the output of the module. During an outage, the inverter continues to operate, supporting power to the load from the battery supply. If the unit requires service, applied loads are transferred to the internal bypass,
7.2.1 Single Module RT Modes
The Powerware 9390 UPS supports a critical load in three different modes of operation. The UPS can automatically use all three modes, as required. The standard operation modes are:
In Normal mode, the critical load is supplied by the inverter, which derives its power from rectified utility AC power. In this mode, the battery charger also provides charging current for the battery, if needed.
In Battery mode, the battery provides DC power, which maintains inverter operation. The battery supports the critical load.
In Bypass mode, the critical load is directly supported by utility power.
EATON Powerware® 9390 UPS |
