GE 40, 20, 10, 30 manual 13

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GE

3.2.3Utility recovery operation

As soon as the AC input power recovers, the Rectifier will start automatically, supplying DC power to the Inverter and recharging the Battery.

If the Inverter was previously shut down due to low Battery, the Load will be initially powered by Utility through the Automatic Bypass.

When the Battery is recharged enough to ensure a minimum time of operation with the present load, the Inverter will start automatically and the Load will be transferred back to the Inverter.

Fig. 3.2.3-1 Block diagram Utility recovery operation

In case of parallel operation

When the AC input power recovers, the Rectifiers will start up sequentially, according to their number in the parallel system. This minimizes the initial inrush current.

The Inverters will start up automatically, but only when the Battery has recharged enough for a minimum runtime with the present load.

When enough Inverters to supply the Load have been restarted, the Load will be transferred from the Automatic Bypass back to the Inverter output.

3.2.4 Automatic Bypass

In normal operation, the Load is supplied by the Inverter.

When the control system detects a fault in the Inverter, an overload condition or a short-circuit condition, the Automatic Bypass will transfer the critical Load to the Utility without interruption.

When the Inverter recovers, or the overload or short-circuit condition is corrected, the Load will be automatically transferred back to the Inverter.

If the UPS is unable to return to normal mode following an automatic transfer to Bypass mode, an alarm condition will be initiated.

A Manual Bypass (operator initiated) will not be considered as an alarm condition.

FIG. 3.2.4-1 BLOCK DIAGRAM AUTOMATIC

BYPASS

In case of parallel operation

Each unit has it’s own internal Bypass. These units are continuously exchanging information, enabling all of the internal Bypass circuits in a parallel system to operate simultaneously.

If the Inverter of a unit fails, it’s Bypass circuit remains available to the parallel system.

It is excluded only if the unit is separated from the common bus by opening it’s output switch Q1.

3.2.5Manual Bypass

The Manual Bypass circuit consists of Q1 and Q2 manual switches, which permits transfer of the Load directly to the unconditioned AC power without interruption, leaving the UPS available for maintenance.

Fig. 3.2.5-1 Block diagram Manual Bypass

OPM_SGS_USM_10K_40K_0US_V010.doc 13/88 Operating Manual SG Series 10, 20, 30 & 40 kVA