Chapter: H.3. Installation
a. Separation
Power cables (supplying, motor's) must be separated from signal wires. It is necessary to avoid parallel
leading of power and signal wires in the common wire channels, and especially in group of cables. The
crossing of power cables and signal cables under a right angle is allowed.
b. Equipotential connections
The frequency converter and the filter should be mounted as close as possible, preferably on a common
metal plate which act as a ground. For this purpose you can use, a mounting plate or a back wall of a case
for example. The casing of the frequency converter, the filter and the metal plate shouldn't be coated with any
insulation materials. It is necessary to pay attention to an opportunity of oxidation of a surface that results in
deterioration of contact. For limitation of asymmetric disturbance level, it is necessary to apply many
connections of the cable shielding to ground.
c. Shielding
Wires between the mains filter and the frequency converter are not necessary for shielding, if their length
doesn't exceed 300mm. In case the length of conductors exceeds 300mm it is necessary to use the shielded
wires. Completely shielded cable is a cable which fully complies with requirements of interference radiation
according to EN 55011 norms. Such cable should have the screen consisting of spiral metallized aluminium
foil and tinned copper plait with a puls-duty factor of not less than 85 %, not separated galvanically.
Connection of the cable ends to ground is obligatory. It is necessary to use grounding of the cable shielding
on whole section of a cable, on both ends. For this purpose a special EMC grommets are used. They provide
valid contact of cable shielding to the case of the equipment. In addition it is necessary to use special cable
clips to connect it to back wall of a case for example. It is necessary to pay attention that the unshielded
cables, are as short as possible. Junctions of the shielding with a ground should be free from insulating coat
on a whole section. Be careful not to damage the shielding. It is not recommended to weave the copper plait
in one point (without using EMC grommet) in order to realize grounding.
In case of need control signal wires should also be shielded using the same principles.
d. Filtration
Use of the EMC filter limits noises spreading from electric drive system to mains. Principles of filter installation
are described at the description of equipotential connections and shielding.
e. Ferrite rings
The reduction of interference emission can be obtained by using ferrite rings located on the input wires
(power supply wires) and output wires (to an electric motor).
f. The list of the equipment reducing EMC problems
The list contains the equipment which can be additionally established in the electric drive system to increase
its noise stability and to reduce emission of interferences in the certain environment of operation.
1. completely shielded cables - we recommend cables TOPFLEX EMV and TOPFLEX EMV 3 PLUS
(HELUKABEL),
2. EMC grommets (throttles),
3. Ferrite rings,
4. RFI filter (REO, SCHAFFNER),
5. EMC case - an option, which is not necessary for fulfillment of the EMC instructions.
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MFC1000AcR, TWERD Power Electronics
