Installation and commissioning
DIGIDRIVE
Variable speed drive
28
Réf. 3218 GB - 4.33 / d - 02.02
LEROY-SOMER
3.5.3.3 - Recommendations
An installation consisting exclusively of
devices which comply with the
standards concerning immunity is very
unlikely to be subject to a risk of
interference.
3.5.4 - Radio frequency interference:
Emission
3.5.4.1 - General
Variable speed drives use high-speed
switches (transistors, semi-conductors)
which switch high voltages (around 550V
for 3-phase drives) and currents at high
frequencies (several kHz). This provides
better efficiency and a low level of motor
noise.
As a result, they generate radio frequency
signals which may disturb operation of
other equipment or distort measurements
taken by sensors:
- due to high-frequency leakage currents
which escape to earth via the stray capacity
of the drive/motor cable and that of the
motor via the metal structures which
support the motor
- by conduction or feedback of R.F. signals
on the power supply cable: conducted
emissions
- by direct radiation near to the mains
supply power cable or the drive/motor
cable: radiated emissions
These phenomena are of direct interest to
the user.
The frequency range concerned (radio
frequency) does not affect the energy
distribution company.
3.5.4.2 - Standards
The maximum emission level is set by the
generic industrial (EN 50081-2) and
domestic (EN 50081-1) standards.
3.5.4.3 - Recommendations
• Experience shows that the levels set
by standards EN 50081-1 and 50081-2 do
not necessarily need to be respected to
eliminate interference phenomena.
• Following the basic precautions in the
next paragraph generally results in
correct operation of the installation.
3.5.5 - Basic precautions
These are to be taken at the design stage
and also when wiring the cabinet and the
external elements. In each paragraph, they
are listed in decreasing order of effect on
correct operation of the installation.
3.5.5.1 - Design
1) Choice of equipment
Give priority to components whose level of
immunity conforms to the generic immunity
standards EN 50082-1 and EN 50082-2,
and mount them in a steel cabinet.
2) Location of the drive
Install the drive as close as possible to the
motor to reduce the length of the cable.
3.5.5.2 - Installation of the drive and
associated components in the cabinet
1) Screw the drive and the components on
to a metal grille or a base plate which is
unpainted or paint-free at the fixing points.
2) Fix the plate at several paint-free points
at the back of the cabinet.
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