Specifications

130BA138.10
Illustration 3.11 LCP Kit with Graphical LCP, Fasteners, 3 m
Cable and Gasket
Ordering No. 130B1113
130BA200.10
Illustration 3.12 LCP Kit with Numerical LCP, Fasteners and
Gasket
Ordering no. 130B1114
3.1.14 Output Filters
The high-speed switching of the frequency converter
produces some secondary effects, which influence the
motor and the enclosed environment. These side effects
are addressed by 2 different filter types, the dU/dt and the
sine-wave filter.
dU/dt filters
Motor insulation stresses are often caused by the
combination 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 and rapid energy
change in the motor. This reduction prevents 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 frequency converter
to the motor. The voltage wave form is still pulse-shaped
but the dU/dt ratio is less than the installation without
filter.
Sine-wave filters
Sine-wave filters are designed to let only low frequencies
pass, resulting in a sinusoidal phase-to-phase voltage
waveform and sinusoidal current waveforms.
With the sinusoidal waveforms, special frequency converter
motors with reinforced insulation are no longer needed.
The acoustic noise from the motor is also reduced as a
consequence of the wave condition.
Besides the features of the dU/dt filter, the sine-wave filter
also reduces insulation stress and bearing currents in the
motor, thus leading to prolonged motor lifetime and
longer periods between services. Sine-wave filters enable
the use of longer motor cables in applications where the
motor is installed far from the frequency converter. The
length is limited because the filter does not reduce
leakage currents in the cables.
Selection VLT® HVAC Drive FC 102 Design Guide
60 MG16C102 - Rev. 2013-08-20
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