Output Filters
The high speed switching of the frequency converter
produces some secondary effects, which influence the
motor and the enclosed environment. These side ef-
fects are addressed by two different filter types, -the
du/dt and the Sine-wave filter.
dU/dt filters
Motor insulation stresses are often caused by the com-
bination of rapid voltage and current increase. The
rapid energy changes can also be reflected back to the
DC-line in the inverter and cause shut down. The du/
dt filter is designed to reduce the voltage rise time/the
rapid energy change in the motor and by that inter-
vention avoid premature aging and flashover in the
motor insulation. du/dt filters have a positive influence
on the radiation of magnetic noise in the cable that
connects the drive to the motor. The voltage wave form
is still pulse shaped but the du/dt ratio is reduced in
comparison with the installation without filter.
Sine-wave filters
Sine-wave filters are designed to let only low frequen-
cies pass. High frequencies are consequently shunted
away which results in a sinusoidal phase to phase
voltage waveform and sinusoidal current waveforms.
With the sinusoidal waveforms the use of special fre-
quency converter motors with reinforced insulation is
no longer needed. The acoustic noise from the motor
is also damped as a consequence of the wave condi-
tion.
Besides the features of the du/dt filter, the sine-wave
filter also reduces insulation stress and bearing cur-
rents in the motor thus leading to prolonged motor
lifetime and longer periods between services. Sine-
wave filters enable use of longer motor cables in ap-
plications where the motor is installed far from the
drive. The length is unfortunately limited because the
filter does not reduce leakage currents in the cables.
Ordering Numbers: Sine Wave Filter Modules,
200-500 VAC
Mains supply 3 x 200 to 500 V
Minimum switching frequency
Maximum output fre-
quency
Part No. IP20 Part No. IP00 Rated filter current at 50Hz
5 kHz 120 Hz 130B2439 130B2404 2.5 A
5 kHz 120 Hz 130B2441 130B2406 4.5 A
5 kHz 120 Hz 130B2443 130B2408 8 A
5 kHz 120 Hz 130B2444 130B2409 10 A
5 kHz 120 Hz 130B2446 130B2411 17 A
4 kHz 60 Hz 130B2447 130B2412 24 A
4 kHz 60 Hz 130B2448 130B2413 38 A
4 kHz 60 Hz 130B2307 130B2281 48 A
3 kHz 60 Hz 130B2308 130B2282 62 A
3 kHz 60 Hz 130B2309 130B2283 75 A
3 kHz 60 Hz 130B2310 130B2284 115 A
3 kHz 60 Hz 130B2311 130B2285 180 A
3 kHz 60 Hz 130B2312 130B2286 260 A
3 kHz 60 Hz 130B2313 130B2287 410 A
3 kHz 60 Hz 130B2314 130B2288 480 A
2 kHz 60 Hz 130B2315 130B2289 660 A
2 kHz 60 Hz 130B2316 130B2290 750 A
2 kHz 60 Hz 130B2317 130B2291 880 A
2 kHz 60 Hz 130B2318 130B2292 1200 A
NB!
When using Sine-wave filters, the switching frequency should comply with filter specifications in par.
411 Switching Frequency.
VLT
®
5000 Design Guide
24 MG.52.B2.02 - VLT
®
is a registered Danfoss trademark
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