EMC Manual ServodynT, D
Motor, sensor lines
43
1070 066 074-101
4.3
Lines in special machines and in systems
Special machines and systems do not generally have closed covers. They
can also be distinguished by the larger dimensions which require motor
lines longer than 25 m.
Unscreened
In order to reduce interference emissions, the motor lines should be as
motor lines
short as necessary and generally in or directly on top of metal strutural
parts, e.g.
If there are no metal structural parts present, use screened lines.
Ferrite annular cores reduce electromagnetic emissions in the frequency
range > 30 MHz, see typical configurations in section
.
Screened
Where screened lines and lengths of over 25 m are involved, the mains
motor lines
filter is put under additional strain from the considerably larger coupling
capacities. They may also cause operationrelated shutdowns.
The interference voltages on the mains supply cable must therefore be
measured and, if necessary, the type B mains filter employed.
Ferrite annular cores are also required with screened motor lines, as they
reduce electromagnetic emissions in the frequency range > 30 MHz, see
typical configurations in section
.
Long lines
Long lines are prone to frequent gains and losses of interference. This ef
fect can be minimised by laying out interferenceemitting and interfe
rencesensitive lines separately.
The required distance between motor lines and control lines is:
d
> 100 mm with parallel laying of < 10 m
d
> 250 mm with parallel laying of > 20 m
Install the drive inverter close to the motors in order to ensure, if possible,
that motor lines do not exceed 25 m in length.
Crossed lines
Where lines are crossed, interference will be at its lowest if the angle at
which they cross is 90°.
Interferencesensitive lines should therefore cross motor lines or ballast
resistor lines only at an angle of 90°.
Output filters
Motor impeders, dU/dt filters or sinusoidal filters can only be employed for
frequency converters or controlling the standard motors.
These output filters may
not be employed
for servo drives and mains
spindle drives.
LSA Control S.L. www.lsa-control.com [email protected] (+34) 960 62 43 01
