How to connect the shielding of cable to a Earth potential?
All modern power stages of motor controllers use PWM voltages to control the motor supply. Such PWM power signals can result in some EMI radiation and can have a negative impact on sensitive sensor signals (e.g. hall sensors, analog sensors, video signals). Therefore it is recommended to use shielded motor cables. This recommendation is especially important in case of ...
- ... long motor cables.
- ... motor cables which are placed close to sensor cables.
- ... high motor currents.
The cable shielding has to be attached to Earth at least on one side of the cable. If the cable length exceeds 1 or 2 meters, it is recommended to attach the cable shielding on both cable ends to the Earth potential.
A motor cable shield can be quite easily attached to an earthed part of a metal structure (e.g. of a cabinet or machine) by so-called earthing clamps. The earthing clamps should be placed close to the controller and motor. This is the same solution like in use for more powerful servo drives and frequency converters which can be used for maxon motors and controllers too.
- Strip the insulation close to the motor cable ends.
(Typically within the last 10 cm of the cable).
- Mount the earthing clamps on an earthed metal piece of the cabinet or your machine close to the controller and motor.
- Plug the shielding of the cable into the earthing clamp.
Ensure that the diameter of the Earth clamp fits to the diameter of the cable and there is a close and extensive contact in between the cable shielding and the Earth clamp.
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