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3 DESCRIPTION

GE

3.1BLOCK 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.

RectifierThe 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.

InverterThe 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.

BatteryThe Battery supplies the DC power to the Inverter when the Utility is out of accepted tolerances.

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Operating Manual SG Series 10, 20, 30 & 40 kVA