GE Industrial Solutions SG Series 10 – 20 – 30 – 40 kVA Operating Manual - Manual (Page 11)

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OPM_SGS_USM_10K_40K_0US_V030.doc Operating Manual SG Series 10 –20 – 30 - 40 kVA
3 DESCRIPTION
3.1 BLOCK DIAGRAM AND MAIN ELEMENTS
Fig. 3.1-1 Block diagram
The SG Series system can be divided into the following main elements:
Control System SG Series 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 K8 (in series with the thyristors of the
static switch) and eventually K7, and acts in case of internal defects of the system, or due to wrong
manipulations on the Manual Bypass Q2.
Manual Bypass 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.