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NS3000 Series User Manual rev.01
2.4.1.1 Rectifier and Bypass Input Supply of the UPS
Install suitable protective devices in the distribution unit of the incoming mains supply, considering the power cable
current-carrying capacity and overload capacity of the system. Generally, the magnetic circuit breaker with IEC60947-2
tripping curve C (normal) at the 125% of the current listed in table 2-1 is recommended. Whith common input we suggest
tripping curve d
Note
For IT power network system, 4-pole protective device must be installed on the external input distribution of the
UPS.
Earth leakage current
If protection against earth faults (RCD devices) is required for the upstream of the input supply, the installed device
should:
l
Sensitive to DC Class B or class A in the network
l
Insensitive to transient current pulses
l
Have an average sensitivity that is adjustable between 0.3A-1A
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NS3000 Series User Manual rev.01
2.4.1.2 Backfeed Protection.
Put a label on all
primary power
isolators installed remote from the
UPS
area. One label is supply
Before working on this circuit
- Isolate Uninterruptible Power System (UPS)
- Then check for Hazardous Voltage between all terminals
including the protective earth
Risk of Voltage Backfeed
UPS whit by-pass and line input separate
UPS whit by-pass and line input common
Pay attention Neutral is common point inside UPS.
L11
L21
L31
N1
Q
UPS
Byp. terminal
T1
L1
L2
L1ma
N
L3
L2 mb
L3mc
N
Q
Imput terminal
Customer distribution
L1 ba
L2 bb
L3bc
N
L11
L21
L31
N1
Q
UPS
UPS Input teminals
T1
L1ma
L2 mb
L3mc
N
Customer distribution
L1 ba
L2
L3bc
N
