Xylem HYDROVAR (HV2.1 - 3.45) - Manual (Page 23)

23
6.2 EMC-electromagnetic compatibility
To ensure the electromagnetic compatibility the following points must be observed for cable
installation:
Earth / ground to ensure EMC
• Protection earth
It is important to connect the HYDROVAR to PE, because of the earth leakage current.
• HF earth connection
Ground cables should be as short as possible and with lowest impedance.
Signal cables
Control and signal cables should be screened types to prevent disturbances from outside.
The screen should be only connected to ground on one side; otherwise it is possible that the
screen has a ground current. The screen should be connected with cable-clips extensive to
HYDROVAR GND.
Signal cables should be installed separate from motor- and power- supply cables
If signal cables are installed in parallel to motor-cables or to power supply cables for a longer
distance, the distance between these cables should be more than 200mm.
Don’t cross power cables with control cables-if this is not possible, cross them only 90°
Motor cables
To prevent EMC and capacitive currents, we advise to install the HYDROVAR directly at the
motor. If the HYDROVAR is mounted separately, keep the motor cable as short as possible.
We recommend using a screened cable or one protected by a metal sheath.
• It is necessary to connect both ends of the screen to ground, but these connections
couldn’t replace the potential equalization.
• We suggest a cable-clip for an optimal connection of the screen.
• Pigtails should be prevented, because they raise the impedance of the screen and affect the
shielding effect at a high frequency.
• The power cable and the motor cable should be installed as distant as possible.
For motor cable lengths from 20 to 100 meters it is necessary to install an output filter
between the HYDROVAR and the motor as shown in the diagram below.
The filter has to be mounted as close as possible to the HYDROVAR (max. distance 2 meters).
For further information contact our sales or service department.