User`s guide

170
CHAPTER 8 - CFW-08 OPTIONS AND ACCESSORIES
Table 8.4
- Alternative criteria for use of line reactor - maximum values of the
transformer power
TransformerApparent Power [kVA]
1.6 A and 2.6 A/200-240 V
4A/200-240 V
7 A and 7.3 A/200-240 V
10A/200-240 V
16-22-28A and 33 A/200-240 V
1 A-1.6 A and 2.6A/380-480 V
4.0 A and 4.3 A/380-480 V
2.7 A/380-480 V
6.5-10A and 13 A/380-480 V
16-24A and 30 A/380-480 V
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]
InverterModel
Note:
The value for the rated apparent power can be obtained in
item
9.1 of this
manual.
The use ofa three-phase load reactor, withanapproximate 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 inverterand motor(as a function of the "transmission
line" effect) are used.
Thereare manyfactors 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 notalways 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 (refer to item 8.21.1).
If the cables between inverter and motor are longer that 100 m
(300 ft), the cable capacitance to ground maycausenuisance
overcurrent (E00) trips. In this case it is also recommended to
use a load reactor.
8.22
LOAD REACTOR