Liebert PDUTM, STS2 System Components, Electrical Requirements, Surge Suppression, Response Time

Specifications

14.1.6Electrical Requirements

Table 23 Electrical requirements

Item	Requirement
Maximum Continuous Current	250, 400, 600, 800 amps
Load Power Factor Range	0.75 to 1.0, leading or lagging
Load Crest Factor	Up to 3.5
Source Voltage Distortion	Up to 10% THD with notches and ringing transients
	125% for 30 minutes 250A-400A
Overload Capability	125% for 10 minutes 600A-800A
	150% for 2 minutes
	500% for 0.25 sec

Table 24 Unit short circuit withstand capability

Unit Voltage	Unit Amps	Withstand Capability
	250A	100kA
208-240V	400-600A	100kA
	800A	100kA
	250A	65kA
380-480V	400-600A	100kA
	800A	65kA
	250A	25kA
600V	400-600A	25kA
	800A	42kA

14.1.7Surge Suppression

The static transfer switch is equipped with transient voltage surge suppression on each input for surge suppression. The surge suppression is capable of protecting the static transfer switch from operating outside of tolerances due to surges as defined by IEC 1000-4-5 (1.2/50uS surge, 2kV CM and 1kV DM) as required under EN 50091-2. Optional surge suppression modules (TVSS) are available for each input of the STS2/PDU for surge protection of the transformers.

14.1.8Response Time

A dual level fast/slow transfer threshold is used for under voltage detection to allow the STS2/PDU to be compatible with UPSs and generators. The voltage thresholds and the slow transfer delay time is user-adjustable. The fast transfer delay time is less than 4 ms.

The over voltage detection uses a single threshold, with programmable level and delay time. See User Settings on page 101 for instructions on configuring these settings.

14.1.9Environmental Requirements

See 3.0 - Locating The STS2/PDU for details concerning environmental requirements for the STS2/ PDU.

14.2System Components

All STS2/PDU models provide two isolation transformers connected to a solid-state, three-pole dual- position static transfer switch within one enclosure, with the ability to transfer between two input sources to a single output.

All STS2/PDUs are configured with an LCD Color Graphical Interface touch screen display for moni- toring and configuring the unit.

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