75
CC 460V Series Interconnection
Additional precautions to limit EMI and RFI
The use of the recommended filters and installation as detailed will reduce EMI and RFI
to the limits specified by the EC directives. However, additional precautions and equip-
ment may be necessary to provide practical solutions to any interference caused by vari-
able speed drives. These are detailed below:
1.
It is usually necessary to screen the cable between the inverter and motor. The
screen must be earth ground directly to the inverter earth and the motor earth. Use
a clamp style earth connection around entire shield.
2.
The length of the cable between the inverter and motor must be kept as short as
possible to limit cable capacitance. If cable length exceeds 50m, an output induc
tor may be required.
3.
The connections in the screening system must provide a low impedance at high
frequencies. To achieve this additional clamping, removal of paint or use of spe
cial connectors may be required.
4.
Control and signal cables must be shielded and separated from power cables. A
distance of 30cm is usually adequate. Where control or signal cables cross power
cables, this must be done at 90 degrees.
5.
The use of ferrite core inductors on the input or output and capacitor filters on the
input may provide some additional filtering for specific applications where
interference exist. Consult Drivecon Corporation for more details.
