GE Industrial Solutions SG Series 400 & 500 Operating Manual - Manual (Page 12)

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OPM_SGS_USM_M40_M50_2US_V010.doc User Manual SG Series 400 & 500 UL S2
4 DESCRIPTION
4.1 BLOCK DIAGRAM AND MAIN ELEMENTS
Fig. 4.1-1 Block diagram
The SG Series 400 & 500 system can be divided into the following main elements:
Control System
SG Series 400 & 500 is designed with microprocessor-controlled signal processing circuits.
The interface between the operator and the unit is provided by the monitoring system on the front panel.
This monitoring system consists of an active mimic diagram, a keyboard and a backlit display.
Rectifier
The standard Rectifier consists of a 6-pulse SCR-bridge, which converts the 3-phase Utility Voltage into a
controlled and regulated DC-voltage.
This regulated DC-voltage is used to supply power to the Inverter, and to provide charging power to the
Battery.
Inverter
The Inverter converts the DC voltage into a three-phase AC-voltage with constant amplitude and
frequency, which is completely independent and isolated from the AC-input voltage.
Automatic Bypass
The Automatic Bypass consists of a static semiconductor-switch (SSM: Static Switch Module), used to
provide an uninterrupted transfer of the Load from Inverter to Utility.
Back-feed Protection
All SG Series UPS's are equipped with an automatic system for the protection against voltage back
feeding towards Utility, through the Bypass (Applied Standard IEC 62040-1).
This protection works automatically by opening contactor K6 and eventually K7, and acts in case of
internal defects of the system, or due to wrong manipulations on the Manual Bypass Q2 (option).
Manual Bypass (option)
The Manual Bypass consists of a pair of manual switches (Q1 and Q2), which removes the UPS from the
Load for maintenance, while still supplying the Load with power directly from the Utility.
Battery
The Battery supplies the DC power to the Inverter when the Utility is out of accepted tolerances.