Omron L7Z Quick Start Manual page 7

2. Measures to Ensure Conformity of Omron-Yaskawa Motion Control Frequency
Inverters to the EMC Directive
Omron-Yaskawa Motion Control frequency inverters do not necessarily have to be installed in a switch cabi-
net.
It is not possible to give detailed instructions for all of the possible types of installation. This manual therefore
has to be limited to general guidelines.
All electrical equipment produces radio and line-borne interference at various frequencies. The cables pass
this on to the environment like an aerial.
Connecting an item of electrical equipment (e.g. drive) to a supply without a line filter can therefore allow HF
or LF interference to get into the mains.
The basic countermeasures are isolation of the wiring of control and power components, proper grounding and
shielding of cables.
A large contact area is necessary for low-impedance grounding of HF interference. The use of grounding
straps instead of cables is therefore definitely advisable.
Moreover, cable shields must be connected with purpose-made ground clips.
3. Laying Cables
Measures Against Line-Borne Interference:
Line filter and frequency inverter must be mounted on the same metal plate. Mount the two components as
close to each other as possible, with cables kept as short as possible.
Use a power cable with well-grounded shield. Use a shielded motor cable not exceeding 20 meters in length.
Arrange all grounds so as to maximize the area of the end of the lead in contact with the ground terminal (e.g.
metal plate).
Shielded Cable:
Use a cable with braided shield.
•
Ground the maximum possible area of the shield. It is advisable to ground the shield by connecting the
•
cable to the ground plate with metal clips (see following figure).
The grounding surfaces must be highly conductive bare metal. Remove any coats of varnish and paint.
– Ground the cable shields at both ends.
– Ground the motor of the machine.
Ground clip Ground plate
EN-4