Load Reactor - WEG CFW08 Vector inverter User Manual

CFW-08 OPTIONS AND ACCESSORIES

8.16 LOAD REACTOR

130
PE
R
S
T
Line
(b) Three-phase power supply models
Figure 8.21 - Power connection with line reactor at the input
As an alternative criterion, we recommend to add a line reactor
always the transformer that supplies the inverter has rated output higher
than indicated in table below.
Inverter Model
1.6A and 2.6A/200-240V
4A/200-240V
7A and 7.3A/200-240V
10A/200-240V
16A/200-240V
1A; 1.6A and 2.6A/380-480V
4.0 and 4.3A/380-480V
2.7A/380-480A
6.5;10A and 13A/380-480
16A/380-480
Note: The value for the rated apparent power can be obtained in section 9.1 of this
manual.
Table 8.4 - Alternative criteria for use of line reactor -
Maximum values of the transformer power
The use of a three-phase load reactor, with an approximate 2% voltage
drop, adds an inductance at the inverter PWM output to the motor. This
decreases the dV/dt (voltage rising rate) of the pulses generated at the
inverter output. This practice reduces the voltage spikes on the motor
windings and the leakage currents that may be generated when long cables
between inverter and motor (as a function of the "transmission line" effect)
are used.
There are many factors that influence the peak level (Vp) and the rise time
(tr) of voltage spikes: cable type, cable length, motor size, switching
frequency and so on.
WEG recommends using a load reactor when the supply voltage is higher
than 500V, though this is not always required.
WEG, as a specialist in both motors and inverters (VSDs) is able to
provide an integrated solution.
The load reactor value is calculated in the same way as the line reactor
(see item 8.15.1).
If the cables between inverter and motor are longer that 300 ft (100 m), the
cable capacitance to ground may cause nuisance overcurrent (E00) trips.
In this case it is also recommended to use a load reactor.
U V W
R S T
P E P E
Shield
Transformer Apparent Power [kVA]
30 x rated inverter apparent power [kVA]
6 x rated inverter apparent power [kVA]
10 x rated inverter apparent power [kVA]
7.5 x rated inverter apparent power [kVA]
4 x rated inverter apparent power [kVA]
30 x rated inverter apparent power [kVA]
6 x rated inverter apparent power [kVA]
15 x rated inverter apparent power [kVA]
7.5 x rated inverter apparent power [kVA]
4 x rated inverter apparent power [kVA]
P E W V U