Liebert UPS System user manual Fault and Fault Process Methods

Chapter 8 Parallel System

This figure only shows the connection method of control cables of parallel operation system with 3 UPS units. The others can be done according to the same methods.

1 2 3 4

1 2 3 4

1 2 3 4 Emergency stop button

Fig. 8-6 Emergency shutdown button

Where, “1”-Normally closed contacts for emergency shutdown “2”- Central contacts for emergency shutdown

“3”- Normally open contacts for emergency shutdown “4”- Normally closed contacts for common alarm

8.5.6 Fault and Fault Process Methods

The faults of single module UPS system is given in Chapter 7. The faults that specially belong to the parallel operation system are given in Table 8-3. If some UPS unit has fault, it can exit the system and other units can maintain the normal operation mode. But redundancy is not available, so the faulty UPS unit must be repaired as soon as possible.

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