Modes of Operation

7.0MODES OF OPERATION

7.1Normal Mode

During Normal mode operation, the PowerSure PSI supplies conditioned, computer-grade power to the connected equipment: mains power passes through the TVSS circuitry and the EMI/RFI filters and then through the Inverter (1000VA & 1440VA) / Bi-Directional Converter (2200VA & 3000VA) to connected equipment.

When the UPS is in Normal mode, the AC Input Indicator illuminates green. The UPS display in Figure 13 shows the UPS operating in Normal mode with 26% - 50% load connected to the output.

Figure 13 Normal mode operation with 26-50% load

Mains power present ...

... and within operational limits

The PowerSure PSI continuously monitors the batteries to maintain them in a fully charged state. The battery charger operates whenever AC power is present, even if the UPS is switched Off. By default, the UPS is set to perform an automatic battery test after it has been operating continuously for two (2) weeks. The automatic battery test can be disabled via MultiLink.

7.2Buck/Boost Mode

The Automatic Voltage Regulator (AVR) circuitry compensates for fluctuations in mains power, such as voltage surges and sags. When the PowerSure PSI detects an abnormality, it raises the undervolt- age (boost) or lowers the overvoltage (buck) as needed. The AVR operates automatically and main- tains the output voltage to the connected critical equipment, without utilizing the batteries.

The Buck/Boost Indicator flashes green when the UPS is operating in Buck mode and illuminates green when the UPS is operating in Boost mode (see 11.0 - Troubleshooting for details).

Figure 14 Buck/Boost mode operation with 51-75% load and 21-40% battery capacity

Indicator shows UPS in Boost Mode (solid green)

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Liebert PSITM user manual Normal Mode, Buck/Boost Mode, Modes of Operation, Mains power present Within operational limits

PSITM specifications

The Liebert PSITM is an advanced power protection system designed to ensure the reliability and efficiency of critical systems in data centers, industrial applications, and mission-critical environments. As the demand for uninterrupted power supply continues to grow, the Liebert PSI serves as an indispensable asset.

One of the main features of the Liebert PSI is its online double-conversion technology. This method guarantees a continuous supply of clean and stable power to connected loads by converting incoming AC power to DC, then back to AC. This process eliminates power disturbances such as voltage sags, surges, and harmonics, ensuring that sensitive equipment operates without interruption.

In addition to its robust power protection capabilities, the Liebert PSI offers scalable solutions to meet varying power requirements. Ranging from 5 kVA to 40 kVA, it can be configured for single or three-phase operation. This flexibility allows businesses to tailor the system to match their specific needs, whether they are expanding data center operations or simply upgrading existing infrastructure.

Another notable characteristic of the Liebert PSI is its energy efficiency. The unit is designed to operate with a high efficiency of up to 94%, which not only reduces operational costs but also minimizes the environmental impact. Moreover, it features an eco-mode that optimizes energy use during non-critical operations without sacrificing reliability.

The Liebert PSI is equipped with advanced communication and management capabilities. It includes an intuitive LCD display for real-time monitoring, enabling users to access vital information about the unit's performance and status. Additionally, it supports various communication protocols such as SNMP and Modbus, allowing for seamless integration into existing management systems.

Furthermore, the Liebert PSI is designed with an emphasis on modularity, allowing for easy upgrades and maintenance. This modular approach reduces downtime and enhances serviceability, ensuring that the system remains reliable throughout its lifecycle.

In summary, the Liebert PSITM stands out as a comprehensive power protection solution that combines cutting-edge technology, energy efficiency, and user-friendly features. Its commitment to safeguarding critical systems against power disturbances makes it a vital component in the infrastructure of any modern data center or industrial setting.