04/10 MN04020001Z-EN
Radio interference suppression
filters
161
Radio interference suppression filters
The external interference suppression filters allow further
limitation of the line-conducted emitted interference in the
relevant environment. The limit values are divided into categories
(C1, C2, C3). Category C1 (e.g. private residential area) allows the
lowest emitted interference, while category C3 describes the
interference level in severely polluted industrial networks.
The observance of the permissible limit values depends on the
length of the motor cable and the switching frequency (f
PWM
) of
the inverter. (a Table 13).
RFI filters have discharge currents to earth, which, in the event of
a fault (phase failure, load unbalance), can be higher than the
rated values. To avoid dangerous voltages, the filters must be
earthed before use.
With leakage currents f 3.5 mA the following must be fulfilled in
accordance with EN 61800-5-1 and EN 50178:
• The protective conductor cross-section must be f
10 mm
2
or
• a second protective conductor must be connected, or
• the continuity of the protective conductor must be monitored.
Engineering note (example):
MMX12AA2D8N0-0 frequency inverter and MMX-LZ1-009
interference suppression filter.
In the “Rated operation” setting, the maximum leakage current
can reach (I
LK
) 25.6 mA (A table 14) At a required maximum
pulse frequency (f
PWM
) of 16 kHz (adjustable at P11.9), the
following motor cable lengths are permissible (A table 14):
• In category C1 : 10 m.
• In category C2 : 30 m.
• In category C3 : 50 m.
With a fixed pulse frequency of 1.5 kHz (P11.9 = 1.5,
P11.10 = 11) a maximum motor cable length of 50 m is
permissible in Category C1.
If “low leakage current” operation is required, the plug must be
refitted on the interference suppression filter to < 3.5 mA. The
maximum leakage current (I
LK
) can reach values of up to 1.7 mA
(A table 13). In this operating mode, the following maximum
motor cable lengths are permissible (A table 13):
• In category C1 : 10 m at a maximum pulse frequency of
4.5 kHz
or 5
m at maximum 6kHz.
• In category C2 : 10 m at a maximum pulse frequency of 6kHz or
5
m at maximum 9kHz.
In category C3 the “low leakage current” operation is not
possible.
h
The interference suppression filters listed here must only
be used in conjunction with the devices of the
MMX…N… series.
h
The MMX-LZ1 and MMX-LZ3 radio interference filters can
be fitted to the side or below the frequency inverter.
h
For mobile applications, a plug connector is permissible
only when a second, permanently installed, earthing
conductor is installed.
Figure 118: MMX-LZ1 schematic diagram
L
N
PE
L
N
Figure 119: MMX-LZ3 schematic diagram
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