Emerson Liebert NX 50 and 60 Hz - Manual (Page 61)

UPS Multi-Module Installation
49
3.3.3 Power Cables
The wiring of power cables is similar to that of single module system except that the output of the
upstream UPS is fed into the bypass input of the downstream UPS, and the load is fed by the down-
stream UPS through its inverter or bypass. The bypass and the main input sources must be refer-
enced to the same neutral potential and input earth leakage monitoring devices, if installed, must be
located upstream of the common neutral sinking point. Refer to the instructions in 1.0 - Single Mod-
ule UPS Installation.
No control wires other than those specified for the single module configuration are required.
Figure 32 Hot standby configuration
Mains L1,
L2, L3, N
UPS1
UPS2
Q1
Rectifier
Inverter
Charger
Q2
Q3
Q5
Q2
Q3
Q5
Rectifier
Inverter
Charger
Q1
L1, L2, L3, N L1, L2, L3, N
Mains L1,
L2, L3, N
Input Distribution
Bypass L1,
L2, L3, N
Bypass L1,
L2, L3, N
UPS1 Output
Upstream Downstream