Rack-mounted system offers multiple cabinet configurations to satisfy AC power needs in data centers, wireless sites and central office environments where dependable pure sine wave power is required.

LORAIN, OH September 19, 2004 -- Emerson Network Power, Energy Systems, a business of Emerson (NYSE: EMR), announces the introduction of the LI48AMCAB modular inverter system for relay rack mounting that can be configured to produce 1kVA to 6kVA of 120 VAC, 60 Hz power from a 48 VDC input. The LI48AMCAB system is housed in 23" equipment shelves that support 1U inverter modules and an optional Static Transfer/Maintenance Bypass Switch.

"The system can be initially configured with as little as one 2U shelf and one 1kVA inverter module. As power requirements grow, additional inverters can be added," said Dennis DelCampo, Vice President of Marketing, Emerson Network Power, Energy Systems. "For the ultimate in reliability, the user should incorporate an additional 2U shelf to hold the Static Transfer Switch and Maintenance Bypass Switch panel," he said.

When the Static Transfer Switch is employed, the AC output of the inverters passes through the switch. The switch is also connected to an AC utility power source. If, for some reason, inverter output is lost, the transfer switch automatically transfers the AC load to the utility source. It is a "no-break" transfer that is accomplished in less than the 16 ms length of one 60 Hz AC cycle. Essentially all equipment, including computers, will "ride through" the transition without loss of function.

Should the Static Transfer Switch fail, activating the Maintenance Bypass Switch routes the AC output of the inverters around the transfer switch, directly to the AC load. Then, the transfer switch may be removed and replaced while the system is in operation.

The inverter modules, designed to share the load, feature the same hot-plugability. "If the system is equipped with enough redundancy (n+1) to support the maximum AC load when one inverter is lost, that inverter can be removed and replaced without shutting down the system," notes (Name). (If too many inverters are lost and the system includes the Static Transfer Switch, the switch will sense that loss and automatically transfer the load to the AC utility power source.)

The AC output from the LI48AMCAB inverter modules is pure sine wave current, contrasted to "quasi sine wave" current, an alternating succession of square waves, produced by some inverters. Problems are sometimes encountered with certain AC loads when they are fed with quasi sine wave current.

Unlike some inverter systems, no central controller is required. Other systems incorporate a controller card to regulate the inverters. Since loss of the controller card can affect the stability of the entire system, a redundant card is sold to backup the first card. In the LI48AMCAB system, the controller function is incorporated in each inverter module, and loss of a module will have no effect on the stability of other inverter modules in the system.

Provisions for multiple DC input feeds to the inverters add another degree of reliability. The user may choose to feed all inverter modules from the single DC bus bar that is attached to the back of the cabinet at the factory. Alternately, the user can remove the bus bar in the field to access separate terminal blocks for each shelf. This allows each inverter module to be connected to a separate breaker/circuit from the battery distribution bay so that loss of one breaker or circuit does not shut down the entire system.

About Emerson Network Power

Emerson Network Power is an Emerson business, which provides a full spectrum of reliable power solutions, including inbound power, connectivity, power supplies, power systems, outside plant products and precision cooling, backed by the largest global services organization in the power industry. These Emerson companies serve the needs of telecommunications networks, data centers, health care and industrial facilities worldwide. For more information, visit www.emersonnetworkpower.com.

About Emerson

St. Louis-based Emerson (www.gotoemerson.com) is a global leader in bringing technology and engineering together to provide innovative solutions to customers in electronics and telecommunications; process control; industrial automation; heating, ventilating and air conditioning; and appliance and tools. Sales in fiscal 2003 were $14.0 billion.

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