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INSTALLATION AND CONNECTION
!
DANGER!
Provide a disconnect device for the power supply of the inverter. This device must disconnect the
power supply whenever necessary (during maintenance jobs, for instance).
!
WARNING!
A contactor or another device that frequently disconnects and reapplies the AC supply to the inverter,
in order to start and stop the motor, may cause damage to the inverter power section. Use control
signals to start and stop the motor. If used, the device in the input cannot exceed one operation per
minute or the inverter may be damaged.
✓
NOTE!
The power supply voltage shall be compatible with the inverter rated voltage.
Power factor correction capacitors are not needed at the inverter input (R/L1, S/L2, T/L3) and shall
not be installed at the output of the inverter (U, V, W).
!
WARNING!
Residual current device (RCD):
When used in the inverter supply, it must have a pick-up current of 300 mA.
Depending on the installation (motor cable length, cable type, multimotor configuration, etc.), the
RCD protection may be activated. Contact the RCD manufacturer for selecting the most appropriate
device to be used with inverters.
Consider the following items for the use of protection devices on the supply side of the inverter such as residual
current devices or isolation monitors:
The detection of a phase-to-ground short-circuit or an insulation fault shall be processed by the user, i.e., the
user shall decide whether to indicate the fault and/or block the inverter operation or both.
Contact the RCD manufacturer for selecting the most appropriate device to be used with inverters in order to
avoid nuisance tripping due to the high frequency leakage currents that flow through the leakage capacitances
of the inverter, cable, and motor system to the ground.
3.2.4.1 IT and Delta Corner Earthed Networks
!
WARNING!
The inverters of the CFW900 line can operate in power supply with a solidly grounded neutral, in
delta corner earthed networks and IT networks (ungrounded neutral or grounding by a high ohmic
value resistor). Exception: inverters of frame A cannot operate in delta corner earthed networks
and resistor-grounded IT networks.
To operate in delta corner earthed networks and IT networks, it is necessary to disconnect the RFI
filter.
Independent of the type of power grid, the inverter must always be connected to protective ground
according to the
Inverters of the CFW900 series can be used in IT networks with grounding made by resistors (except models of
frame A). To that end, remove the grounding screws from the filter capacitors, as shown in
. To access
these screws on frames A, B, C and D, remove the HMI and the front cover. In frame E, it is necessary to remove
the lower front cover.
It is also possible to operate the CFW900 in delta corner earthed networks, except for models of frame A. In these
cases, the grounding screws of the filter capacitors must also be removed, as shown in
30 | CFW900
Summary of Contents for CFW900
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