Liebert UPS System user manual Electrical installation, Power cables, Signal cables

Chapter 8 Parallel System

8.2.2 Electrical installation

1. Power cables

Wiring of power cables is the same with that of single module UPS system.

Note:

The length and specifications of power source cables including the bypass input and UPS output cables should be the same, thus the load can be shared evenly in bypass mode.

2. Signal cables

Wiring of signal cables is the same with that of single module UPS system. Parallel connection cables should be connected.

You can see the holes for parallel connection cables when opening the front door of the UPS system. According to the routes, two parallel connection cables are connected to the P1(P2) and P3(P4) sockets on the ULW2L61M3 parallel board, at the same time tighten the screws between the connector and sockets. P1/P2 on the ULW2L61M3 board are two 15-pin sockets with same functions and are used to transmit parallel logic signal. P3/P4 are two parallel 9-pin sockets with same functions and are used to transmit the load sharing detection signal. The wiring method of parallel connection cables of three UPS units are shown in Fig.8-6.

left post		left post		left post
Logic cable
Load sharing detection	Logic cable	Load sharing detection	Logic cable	Load sharing detection
UPS 1 parallel		UPS 2 parallel		UPS 3 parallel
board
		board		board

Fig.8-6 Connection of Parallel Operation Cables

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