Liebert 130 kVA - Manual (Page 83)

User Manual
Hipulse - Single Phase ‘1+N’ UPS System 130 kVA - 110V
63
Chapter 8
1 + N System
8.1 General
The system can comprise of up to 6 UPS modules of the same power rating and
connected in parallel without the need for a centralized mains static bypass. Instead
the bypass static switches of each UPS share the load when the system transfers to
the main bypass supply.
From a ‘power’ viewpoint, each module is internally identical to the single module
configuration. A 1+N parallel system requires inverter and bypass supplies, inter-
module control signals to manage current sharing, synchronizing and bypass
switching between the module. In the figure 8-1, this is shown as the ‘inter-module
control bus’, which is facilitated through the use of multi-way ribbon cables connected
between the units of the system.
When three or more modules are to be connected in parallel it is recommended that
inductance should be inserted in the static bypass line. This can be installed internal
to the UPS as an option.
For each module it is necessary to program the display panel with the correct rating
and to identify that the internal static switch is being used.