WEG CFW-11 - IT Networks; Power Supply Capacity

Installation and Connection
3
3-22 | CFW-11
3.2.3.1.1 Power Supply Capacity
Suitable for circuits with capacity to deliver no more than:
- 100 kA symmetric at 240 V or 480 V when the inverter is protected by fuses;
- 65 kA symmetric at 240 V or 480 V when the inverter is protected by reverse-type circuit breakers.
For compliance with UL standard and specification of current of fuses and circuit breaker see Table 3.5 on
page 3-22.
Table 3.5 - Fuses and circuit breaker specications according to UL standard
Model
Protection with Fuse Ultra-Fast Inverter Protection With Circuit Breaker
Rated
Current of
Fuse
(Amps Max.)
Ferraz-Shawmut
Semiconductor / WEG
High Speed
Fuse Models
Maximum Power
Supply Short-
Circuit Current
Rated
Current
of Circuit
Breaker
Minimum Cabinet
Dimensions
(Depth X Height X Width)
Maximum Power
Supply Short-Circuit
Current
CFW11 0242 T 4
700 A A70P700-4
100 kA
300 A
600 x 2000 x 800 mm
65 kA
CFW11 0312 T 4 400 A
CFW11 0370 T 4 450 A
CFW11 0477 T 4 600 A
CFW11 0515 T 4
900 A A70P900-4
600 A
600 x 2000 x 1400 mmCFW11 0601 T 4 700 A
CFW11 0720 T 4 800 A
CFW11 0795 T 4
2 x 900 A FNH3-900K-A
1000 A
600 x 2000 x 1400 mm
CFW11 0877 T 4 1000 A
CFW11 1062 T 4 1200 A
CFW11 1141 T 4 1200 A
3.2.3.1.2 IT Networks
ATTENTION!
To use frame sizes F, G and H inverters in IT networks (neutral ungrounded or grounded through a
high ohmic value resistor), or in corner-grounded delta networks, it is necessary to disconnect the
cable with the ring tongue lug from the ground busbar and connect it to the isolated point on the
power terminal block, as showed in the Figure 3.11 on page 3-23 and Figure 3.12 on page 3-23.
This is necessary to avoid damages when operating with a line input short circuited with the ground.
NOTE!
The ground-fault protection (F074) is intended for IGBT protection and may not be activated when
inverter output is shorted to ground, when fed by IT networks.
External insulation monitoring devices should be used for system fault monitoring.