GE Industrial Solutions SG Series 750 T12 UL S2 User Manual - Manual (Page 18)

Modifications reserved Page 18/71
OPM_SGS_USM_M75_M75_2US_V010.doc User Manual SG Series 750 UL S2 & SG Series 750 T12 UL S2
4.4 RECTIFIERS PARALLELED ON THE SAME BATTERY
NOTE !
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 SERVICE ENGINEER 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 - in SG Series 750 & SG Series
750 T12 we already have two rectifiers in parallel - see Fig 4.4-1), 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.
Fig. 4.4-1 Diagram RPA system with Rectifiers on Common Battery
1 –
2 –
3 –
4 – Utility input
External Battery Fuse
Battery
Load Bus Bar
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 completely shut down.
• The AC Rectifiers input power (1) 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 / MCCB (2) 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 / MCCB on the Battery line (2).
• 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 4.1 of the “Installation Guide”).
• 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).