34001813EN/AE - Page 19
2. Installation
Frequency converter (without Bypass AC input)Upstream and downstream: TT, TN or IT system with neutral distributed
Upstream and downstream: Neutral not distributed
Parallel configuration without external bypass cabinet and with common normal and Bypass AC inputs (maximum two units in parallel)The requirements for the different system earthing arrangements (SEA) are similar to those for single UPS
configurations. In the diagrams on page 17, simply replace the single UPS units between points A and B by the
following parallel configuration.
The UPS installation may be equipped with earth-leakage protection upstream on the condition that the protection
apply to:
- the normal and Bypass AC inputs
- all the parallel-connected UPSs.
Main low-
voltage
switchboard
(MLVS)
b Load
Main low-
voltage
switchboard
(MLVS)
b Load
The UPS installation may be equipped with earth-leakage protection upstream on the condition that the protection
apply to:
- the normal and Bypass AC inputs
- all the parallel-connected UPSs.
Normal AC
14
16
15
Normal AC
14
16
15
Normal AC
14
16
14
16
AB
Bypass AC
15
15
Normal AC
Bypass AC