Vertiv Liebert EXL 31, Installer/User Manual

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1 LIEBERT® LOAD BUS SYNC CONTROLLER
The Liebert® Load Bus Sync Controller synchronizes complex power-source systems that consist of different distributions
and static switches supplied by Vertiv™ and other manufacturers when synchronization cannot be guaranteed by the
system configuration or when temporary conditions prevent it, for example, during battery operation.
The Liebert Load Bus Sync Controller is either a factory-installed option or a kit that is installed and configured by Vertiv-
trained and certified personnel. The controller unit is housed in a metal enclosure that may be mounted near the UPS or
inside the electrical distribution panel. It requires a 480V input reference supply and will supply two units.
The controller identifies one of the connected units as the master unit and uses its frequency as a reference for the other
units ("slave" units). While a non-Liebert UPS may be the master, only Liebert UPS's can be slave units. Depending on the
configuration, the slave units always follow the reference frequency or follow only when their reserve utility supply is out of
tolerance. The reference frequency is generated only when the master utility-supply line is within acceptable limits.
The Liebert Load Bus Sync Controller may drive up to two separate units that operate independently or are connected in a
parallel system.
NOTE: When an installation has more than two slave units, or master/slave configuration is not your preferred option,
we suggest using a Liebert MultiBus Synchronization Module (MBSM). Contact your Vertiv sales representative for
details.
The Liebert Load Bus Sync Controller does not affect the system’s mean time between failure (MTBF). It is not a single point
of failure for the system. The individual units will ignore this signal if it is outside the acceptable limits.
The controller dimensions are 3.7 in. x 2.5 in. x 7.1 in. (94mm x 64 mm x 181 mm) width x height x depth.
Table 1.1 below describes the electrical characteristics.
CHARACTERISTIC MINIMUM NOMINAL MAXIMUM
Supply voltage (50/60 Hz sinusoidal), volts 180 480 250
Supply current, mA — 14 —
Output current (per channel), mA 25 — 30
Working temperature °F (°C) 14 (-10) — 104 (40)
Phase stability error — 0.18 —
Phase shift within voltage tolerance range, degrees * — 1.5 °
* Voltage within ±10% of nominal value.
Table 1.1 Electrical Characteristics of the Controller
1 Liebert® Load Bus Sync Controller
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