Liebert 130 kVA user manual + N System, General

User Manual

Hipulse - Single Phase ‘1+N’ UPS System 130 kVA - 110V

Chapter 8

1 + N System

8.1General

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.

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