Moons' MBDV Series - Shielding of Motor Cables; Ferrite Ring

25
Rev. 2.0
07/27/2023
MBDV Hardware Manual
4.1.2 Shielding of motor cables
The selection of motor cables with shielding nets and properly installed shielding nets can achieve
better EMC e󰀨ects and interference suppression e󰀨ects. Please note the following:
• Use shielded cable (Better if there is a double-layer isolation layer)
• The shielding nets at both ends of the motor cable must be grounded with the shortest distance
and maximum contact area. Use clamps to x the shielding nets at both ends of the motor
cable to the metal plane as shown in the gure below. Please refer to the connection method in
the gure below.
• The protective paint should be removed from the xing place between the clamp and the metal
plane to ensure good contact, see the gure below.
Clamp Shielding nets
Metal plate
4.1.3 Ferrite Ring
Ferrite magnetic ring, also referred to as the magnetic ring, can e󰀨ectively absorb the radiation
interference of the wire beam.
The magnetic ring has di󰀨erent impedance characteristics at di󰀨erent frequencies. Generally, the
impedance is very small at low frequencies. When the signal frequency increases, the impedance
of the magnetic ring increases sharply, making it easy for normal and useful signals to pass
through, and can e󰀨ectively suppress high frequencies. The path of interference signals solves the
problem of high-frequency interference suppression of power lines, signal lines and connectors.
When the magnetic ring suppresses common mode interference, the eddy current loss of the
magnetic ring to the high-frequency signal converts the high-frequency component into heat loss,
so that a low-pass lter can be formed, so that the high-frequency noise can be greatly attenuated,
and the impedance of useful signals at low frequencies can be ignored and does not a󰀨ect the
normal operation of the circuit.
The wire passing through the magnetic ring can be repeatedly wound on the magnetic ring to
increase the inductance, thereby enhancing the use e󰀨ect of the magnetic ring. But too many
turns will make the loss too large and the temperature of the magnetic ring will rise too high. The
recommended winding method and number of turns are as follows:
Digital signal Cables Wrap the signal wire around the magnetic ring 2-3 times.
Motor Power Cables
Wind the U/V/W phase of the motor 2-3 times around the magnetic ring.
The ground wire and the shielding net cannot be wound into the magnetic ring.
Encoder Cables Wrap the encoder wire around the magnetic ring 2-3 times.
Magnetic ring recommended model:
MOONS' optional models
Manufacturer's model Manufacturer
M2-OP3035 ZCAT3035-1330 TDK