Vertiv 10H92873, Installation And Operating Instructions Manual

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10H92873 - rev. 8 - 01/2019 - pag. 3
5. TYPICAL CONFIGURATIONS
5.1. TWO SYSTEMS WITH SEPARATE MAINS SUPPLIES
When two UPS are connected to two separate power sources, the inverter attempts to synchronise with their
respective bypass lines, but, since these may not be in phase, synchronisation cannot be guaranteed. Even if
the two units are supplied from a common line, when one, or both, is in battery mode there will be no common
input signal, and the outputs will not be synchronised.
When the External Synchronization Box is installed, one of the UPS outputs must be chosen as the Master, all
the other UPS (Slave) outputs will then follow this reference: see Fig. 3 for details.
Fig. 3 - Two separate mains supplies
N.B. fuses should be installed in the phase signal line, upstream of the Sync. Box in order to protect against the
damage caused by short circuits. If the Master UPS is a 90-NET, these fuses are not required provided the de-
vice is connected to the dedicated terminals - XT1 pins 100 and 200.
Installation tips: UPS B should be configured in order to follow external synchronism signal. This is achieved
by setting the main synchronization source to external signal: otherwise UPS will be in phase with its own by-
pass line and will follow external synchronization only when this is out of tolerance.