Liebert Static Transfer Switch 2, Installation, Operation & Maintenance Manual, Page: 120 / 150

108 Specifications
15.1.4 Grounding
Refer to 5.3 - System Grounding on page 15 for specifications and instructions regarding ground-
ing.
15.1.5 Electrical Requirements
15.1.6 Input Surge Suppression
The STS2 is equipped with transient voltage surge suppression on each input for maximum surge
suppression. The surge suppression is capable of protecting the STS2 from operating outside of tol-
erances 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.
15.1.7 Response Time
A dual level fast/slow transfer threshold is used for under voltage detection to allow the STS2 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 83 for instructions on configuring these settings.
15.1.8 Environmental Requirements
See 3.0 - Location Considerations on page 10 for details concerning environmental require-
ments for the STS2.
Table 20 Electrical Requirements
Item Requirement
Maximum Continuous Current 100, 250, 400, 600, 800, 1000 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
Overload Capability
125% for 30 minutes 100A-400A
125% for 10 minutes 600A-1000A
150% for 2 minutes
500% for 0.25 sec.
Table 21 Unit Short Circuit Withstand Capability
Unit Voltage Unit Amps Withstand Capability
100-250A 100kA
208-240V 400-600A 100kA
800-1000A 100kA
100-250A 65kA
380-480V 400-600A 100kA
800-1000A 65kA
100-250A 25kA
600V 400-600A 25kA
800-1000A 42kA