INSTALLATION AND CONNECTION
3.2.3.1 Input Connections
!
DANGER!
Provide a disconnect device for the inverter power supply. This device must cut off the power supply
whenever necessary (during maintenance for instance).
!
DANGER!
Montez un dispositif de coupure sur l’alimentation du variateur.
Ce composant déconnecte
l’alimentation du variateur si cela est nécessaire (ex. pendant l’entretien et la maintenance).
!
ATTENTION!
The power supply that feeds the inverter must have a solid grounded neutral.
The CFW320 series inverter must not be used in IT networks (where the neutral is not grounded
or grounding provided by a high ohm value resistor) or in grounded delta networks (“delta corner
grounded”), because these type of networks damage the inverter.
✓
NOTE!
The input power supply voltage must be compatible with the inverter rated voltage.
Power factor correction capacitors are not needed at the input (L/L1, N/L2, L3) and must not be
installed at the output (U, V, W).
3.2.3.1.1 Short Circuit Current Ratings (SCCR)
The CFW320 is suitable for use in circuits capable of delivering not more than (see column “SCCR”) kArms
symmetrical at (see column “Voltage”) Volts Maximum, when protected by fuses or circuit breakers as specified
in
or
For inverter’s semiconductor protection, use the WEG recommended class aR semiconductor fuses, according
to
.
For protection in compilance with UL standard, use the protection according to
In case the CFW320 is installed in power supplies with current capacity over the SCCR value specified, it is
necessary to use protection circuits, such as fuses or circuit breakers, proper for those power supplies.
!
ATTENTION!
The opening of the branch-circuit protective device may be an indication that a fault current has been
interrupted. To reduce the risk of fire or electric shock, current-carrying parts and other components
of the inverter or cabinet should be examined and replaced if damaged. If burnout of the current
element of an overload relay occurs, the complete overload relay must be replaced.
3.2.3.2 Power Supply Reactance
In a general way, the inverters of the CFW320 line can be installed directly in the power supply, without reactance
in the supply. However, check the following:
In order to prevent damages to the inverter and assure the expected useful life, you must have a minimum line
impedance that provides a line voltage drop of 1 %. For lower values (due to the transformers and cables), the
use of a line reactance is recommended.
For the calculation of the line reactance necessary to obtain the desired percentage voltage drop, use:
L
= 1592
·
∆
V
·
V
e
I
s,rat
·
f
[
µH
]
CFW320 | 17
