Short Circuit Current Ratings (Sccr); Power Supply Reactance - WEG CFW300 Manual Del Usuario

Installation and Connection
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 CFW300 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
For inverter's semiconductor protection, use the WEG recommended class aR semiconductor
„
fuses, according to Table B2 on page
For protection in compliance with UL standard, use the protection according to
„
on page 133.
In case the CFW300 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 CFW300 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:
Where:
ΔV - desired line drop, in percentage (%).
V - phase voltage in the inverter input, in volts (V).
e
I - rated current of the inverter output.
s, rat
- line frequency.
f
NOTE!
WEG reactors available for CFW300 inverters are listed in the
139.
18 | CFW300
Table B2 on page 130
130.
V
e
L = 1592 . ΔV .
I . f
s, rat
or Table B3 on page
[ μH]
Table B7 on page
133.
Table B3