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Note: The system needs to be checked from time to time to ensure well connection to earth.
1.2 For induction motor
For electrical safety reason, motor must connect to earth with a cable even motor is fixed
on metal construction. The best way is to use green line of the 4-core motor cable to connect
between the frame of the motor and the earth of inverter. Please avoid putting the motor to
earth via busbar.
1.3 For control circuit
If the control circuit of inverter link to any control switches, relays or other similar equipment,
be sure the screened control line is put to earth on single end only. ( a clean earth far from
inverter is recommended)
1.4 For Shielding system
In order to have a very low HF-impedance screening sheath, a Metal clamp and special adapter
are required and the paint on the surface of Metal has to be removed.
2. Shielding
2.1 Inverter will emit EMI via connection cable, therefore, all motor cables, control cables
and signal cables must be screened unless the length of the cable is less than 1 meter.
2.2 The screened motor cable must be put to the earth on both ends, the length of the cable will be
the shorter the better to reduce the stray inductance and capacitance effect.
3. Segregation
3.1 All signal cable and control cable must be separated from unscreened motor cable and
unfiltered power line. The distance should be more than 30cm. The control cable and power
cable should be put perfectly vertically when those two cable crossing each other.
WARNNING
EMI filter can be only used in 3 phase supplies which are nominally balanced with respect to earth.
Never apply EMI filter in a grounded delta supplies system.
