GE Industrial Solutions SG Series 750 T12 UL S2 User Manual - Manual (Page 12)

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OPM_SGS_USM_M75_M75_2US_V010.doc User Manual SG Series 750 UL S2 & SG Series 750 T12 UL S2
4 DESCRIPTION
4.1 BLOCK DIAGRAM AND MAIN ELEMENTS
Fig. 4.1-1 SG Series 750 & SG Series 750 T12 Block diagram
The SG Series 750 & SG Series 750 T12 UPS can be divided into the following main elements:
Control System
SG Series 750 & SG Series 750 T12 are 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
SG Series 750 Rectifier consists of a 6-pulse SCR-bridge, 12-pulse SCR-bridge for SG Series 750 T12, 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
SG Series 750 & SG Series 750 T12 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 External Maintenance Bypass
(option).
Battery
The Battery supplies the DC power to the Inverter when the Utility is out of accepted tolerances.