System Overview

5.1.15Ventilation and Cooling

The Liebert FS stator and power electronics are liquid cooled with a liquid-to-air radiator. The radia- tor within the Liebert FS package is designed for natural and forced air-cooling. Air inlets are pro- vided from the bottom front of the Liebert FS enclosure. Air exhaust is from the top of the unit. Air filters are provided as an option. A minimum 12" clearance overhead is required for the exhaust air- flow.

The Liebert FS was designed with reliability in mind, the radiator is positioned to take advantage of natural cooling and forced-air is only used when there is an elevated temperature. This also applies to the circulating pump for the coolant, which is a highly reliable magnetically coupled centrifugal pump that is powered with a brushless DC motor. This pump operates only when there is an elevated tem- perature within the stator or the PCM, this extends the life of the pump to the point that it will con- tinue to operate over the life of the unit.

5.2List of System User-Configurable Parameters

In order to support a wide set of UPS integrations, the Liebert FS can be configured using the follow- ing operating parameters: See 6.0 - Operation for more information on these parameters and instructions on system setup and entering parameters to system.

Charge Voltage (Vcharge)

Vcharge is the voltage threshold above which the Liebert FS begins to charge/recharge. Vcharge must be set at least 10VDC greater than Vreg.

Range: 360-600VDC

Default setting: 530VDC

Regulation Voltage (Vreg)

Vreg is the voltage setpoint at which the Liebert FS will regulate the DC bus voltage in Discharge Mode

Vreg must be set at least 10 VDC less than Vcharge.

Range: 350-590VDC

Default setting: 520VDC

Maximum Charge Current (Max Charge Current)

Max Charge Current is the Maximum Current the Liebert FS is allowed to draw from the UPS DC bus.

Range—1-50A (typical operation requires a minimum of 3A or 5A)

Default setting—20 A

Charge Conductance (Charge Amps/Volts)

Charge amps/volts is used to set the Liebert FS charging current drawn from the UPS DC bus based upon how much the UPS DC bus voltage is above Vcharge and so without exceeding the Max Charge Current.

Range—0.1-10 A/V

Default setting: 2 A/V

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Emerson 540VDC manual List of System User-Configurable Parameters