Non-Abb Du/Dt Filter Selection; What This Chapter Contains; When A Du/Dt Filter Must Be Used; Filter And Installation Requirements - ABB ACS800 Hardware Manual

Non-ABB du/dt filter selection

What this chapter contains

This chapter contains guidelines for selecting and installing a non-ABB du/dt filter
with the drive.

When a du/dt filter must be used

A du/dt filter must be used with drives of voltages from 500 V to 690 V according to
the Requirements table on page 32.

Filter and installation requirements

1. The filter is an LCR filter or an L filter (i.e. a series inductor: three single-phase
inductors or one three-phase inductor).
Check that the approximate per-phase impedance of the filter inductor is 1.5 %
for drives of frame size R7 and 2 % for drives of frame size R8 when calculated
as follows:
where
Note: Impedances over 1.5 % or 2 % can be used, but then the voltage drop
across the filter will be increased, thus reducing the pull-out torque and attainable
power.
2. The du/dt value of the inverter output voltage is approximately 5 kV /
microsecond. The filter limits the du/dt value at the motor terminals to less than
1 kV / microsecond.
3. The filter withstands the continuous current of the drive (I
the filter core is not allowed up to the maximum output current of the drive (I
4. The filter is dimensioned thermally to withstand a switching frequency of 2 kHz
with 690 V units, and 3 kHz with 500 V units.
5. The cable between the drive and the filter is shorter than the maximum length
specified by the filter manufacturer.
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⋅
3 I N
2 π f ⋅ ⋅ ⋅ ⋅
----------------- - 100
Z = L
L N
U
N
Z impedance of the inductor divided by the nominal phase impedance of the motor, in
=
L
percentage
L per-phase inductance of the filter
=
f rated motor frequency
=
N
I rated motor current
=
N
U rated motor voltage.
=
N
⋅
). Saturation of
cont.max
Non-ABB du/dt filter selection
155
).
max