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GE

3.4RECTIFIERS PARALLELED ON THE SAME BATTERY

A parallel system with a Common Battery for two or more Rectifiers, requires a particular installation and adequate setting of some parameters, (accessible only through password), and can therefore only be done by a qualified engineer from GE.

Usually each Rectifier-Inverter Unit runs with its own Battery.

In case of parallel units are running with a Common Battery (max. 4 UPS - see Fig 4.12-1), the sharing circuit between individual Rectifier is integrated in the communication bus of the system in order to assure an equal sharing of the Rectifiers output currents.

1 – Rectifier

2 – Inverter

3 – Automatic Bypass

4 – Manual Bypass

5 – Mains Power

6 – Load Bus Bar

7 – External Battery Fuse

8 – Battery

Fig. 3.4-1 Diagram RPA system with Rectifiers on Common Battery

Pay attention to the following recommendations:

•The units delivered for this functioning mode needs a special parameters setting, so they must be prepared in advance before the installation.

•The installation must be performed only with the UPS system must be completely shut down.

•The AC Rectifiers input power (5) must be the same, with clockwise phase rotation for each unit.

•Each Rectifier must be set for the same floating DC voltage and the same Battery current limitation.

•It is recommended to install the fuses / MCB (7) on each line connecting the Rectifiers to the common Battery for maintenance / safety reasons.

•In case one must be powered down for maintenance, switch-OFF the concerned unit before open the DC fuses / MCB on the Battery line (7).

•It is recommended to connect an external NO free contact “Battery Fuses” to the UPS and to enable the function by setting the parameter (see Section 7.1).

•If an emergency generator set supply the UPS, and the free contact “Generator ON” is connected to the Customer interface, connect a separate NO free contact on each parallel unit.

•The parameters enabling the Battery test, both manual and automatic, must be set in the same mode on all the units having the Rectifiers on Common Battery.

•Do not connect the temperature sensor for automatic battery floating voltage compensation.

•Do not enable the function Boost charge (parameter 87).

OPM_SGS_USM_10K_40K_0US_V010.doc

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