Vertiv Liebert STS2-PDU
Static Transfer Switch-Power Distribution Unit

Overview:

Provides power distribution and automatic switching between two different AC power sources such as different UPS systems.​​ The Liebert STS2-PDU from Vertiv is making it easier to protect your critical equipment by giving your single cord loads the reliability of dual cord power or by providing added redundancy to your dual cord devices. With a single, space-saving unit, the Liebert STS2-PDU static transfer switch/power distribution unit provides power distribution and automatic switching between two different AC power sources. The Liebert STS2-PDU is available in 250A, 400A, 600A and 800A systems, in both 60Hz and 50Hz. Multiple input voltages are available. Designed for use in dual-bus power applications, this solution combines fast switching between AC power sources, power isolation, distribution, monitoring and grounding into a single package.

An All-In-One Power System With A Smaller Footprint And A Smaller Price Tag

Liebert is making it easier to protect your critical equipment by giving your single cord loads the reliability of dual cord power or by providing added redundancy to your dual cord devices. With a single, space-saving unit, the Liebert Static Transfer Switch 2/Power Distribution Unit provides power distribution and automatic switching between two different AC power sources.

Critical Power Distribution and Switching Made Easy

This is why Liebert designed the STS2/ PDU — to bring you a distribution system that will close the power delivery loop in your critical facility. Liebert STS2/PDU offers the benefits of a custom-tailored power system, with the convenience and cost savings of a pre-packaged, factorytested unit. Housed in a single, selfcontained cabinet, it combines distribution, computer-grade grounding, isolation, and power monitoring, as well as dual-source switching, to provide the protection your vital computer or communications equipment demands. Available in 250 – 800 A capacity systems, the Liebert STS2/PDU offers flexible expansion capabilities to fit growing sites.

A Proven System

The packaged system approach of the Liebert STS2/PDU is convenient and space-saving, reducing installation time and cost compared to a conventional approach using multiple interconnected components. The Liebert STS2/PDU is built on proven system designs used in thousands of installations. And unlike the one-of-a-kind, built-up distribution constructed at the site, it undergoes thorough factory testing as a complete system to assure reliable, consistent performance.

A Reliable Choice for Critical Equipment Protection

A number of integral features allow Liebert STS2/PDU to provide a higher quality level of electrical power for your critical applications:

• Dual AC Input and automatic or manual switching capability boost the availability of reliable power to the protected single-source equipment.
• The main input breaker provides primary transformer overcurrent protection and a power disconnecting means.
• Built-in transformers eliminate harmonic neutral currents, which are possible with building wiring systems.
• Double-shielded isolation transformers located close to the load provide superior noise attenuation.
• Power Distribution:
  • A single output breaker
  • Or, up to four individually enclosed 42 pole output panel boards with panel board main breaker and individual isolated neutral and ground bus bars distribute power to the sensitive load equipment.
  • Or, I-Line Panelboard with up to 10 circuit breakers for distribution to loads, with separate isolated neutral and ground bus bars.
• Oversized neutral components safely withstand neutral currents of at least 1.73 times full load currents.

Designed From The Ground Up For Effective Power Protection

Liebert STS2/PDU is designed with proven-effective Liebert components, combined into a package that greatly improves power quality while saving valuable floorspace.

Computer Grade Grounding
Liebert STS2/PDU establishes a single point ground for the critical load. Power ground and computer ground points are identical, minimizing ground-loop currents and common mode disturbances. Short output cables maintain the integrity of the isolation and conditioning.

Non-Linear Load Compatibility
Liebert STS2/PDU is designed to accommodate moderate levels of harmonic currents. Where severe levels of harmonic currents are anticipated, K-Factor transformers for harmonic current cancellation are available.

Secure Distribution And Circuit Identification
Distribution panels are in the computer room, limiting access to authorized personnel only. Each breaker has an adjacent identification tag for rapid circuit ID.

Dual Input Source for Single Input Loads
The internal solid-state bus transfer switch automatically or manually switches to the second AC source in the event of a power failure, providing true dual source protection for single input equipment.

True Internal Redundancy
In addition to the redundancy provided by the dual internal transformers, the transfer switch itself has triple-redundant logic. Each DSP controller is capable of working independently, and each helps monitor the other two. If one malfunctions, the other two lock it out. Each controller has power feeds from both power supplies.

On-Site Power Monitoring
The integral power monitoring panel provides comprehensive metering and alarms for system power parameters. The color touch-screen LCD monitor has easy to understand pop-up menus, with a wealth of operational and diagnostic information. Monitoring features include:

• True RMS measurements
• Adjustable alarm thresholds
• Programmable custom alarms
• Battery-backed alarm memory

Central Monitoring Interface
Liebert STS2/PDU is compatible with our Liebert SiteScan centralized monitoring systems, allowing single point monitoring and alarm of power conditions. In addition, an isolated RS-232 ASCII port is provided for communication of monitored parameters and alarm information to other monitoring systems. Liebert OpenComms NIC interface card can also be used to enable cost-effective monitoring of a Liebert STS2/PDU by your facility or network monitoring system.

A host of options enable you to design the Liebert packaged power system to your exact needs:

• Up to four, 42 pole panelboards for power distribution to critical equipment.
• I-Line panelboard with 10 circuit breakers for power distribution to the intended loads.
• Transient voltage surge suppression (TVSS) is available for increased protection from damaging voltage surges. Very short interconnecting wiring provides superior surgeclamping performance.
• K20 transformers safely withstand high harmonic currents associated with electronic loads without derating.

Easy Installation And Maintenance In A Compact Footprint

As with all Liebert systems, the Liebert STS2/PDU is a marriage of form and function. In addition to unbeatably reliable power, the unit also saves time with easy installation and routine maintenance while conserving space with its compact package.

Single Cabinet Design

The smart design of Liebert STS2/PDU minimizes installation time while it uses less floorspace. The single cabinet design of the Liebert STS2/PDU is a factory wired and tested, field proven solution requiring less than two thirds the space of traditional built-up systems. This design allows the system to expand with your growth needs, or to easily relocate to a new space if protected equipment is moved to a new facility.

Convenient, Fast Maintenance

The Liebert STS2/PDU requires only front, top or side access for installation, operation and maintenance. Any area requiring routine maintenance is accessed through hinged or easily removed panels. The unit is constructed of replaceable subassemblies that can be easily changed by authorized personnel without exposure to high voltage. Nameplates are provided to identify protected devices, for error-free connection and maintenance.