resistor, and control wiring. Do not run motor wiring from more than one drive in the
same conduit.
￭ Power cable shield
If the cable shield is used as the sole protective earth (PE) conductor, make sure that
its conductivity agrees with the PE conductor requirements.
To effectively suppress radiated and conducted radio-frequency emissions, the cable
shield conductivity must be at least 1/10 of the phase conductor conductivity. The
requirements are easily met with a copper or aluminum shield. The minimum requirement
of the motor cable shield of the drive is shown below. It consists of a concentric layer
of copper wires with an open helix of copper tape or copper wire. The better and tighter
the shield, the lower the emission level and bearing currents.
Insulation jacket1
Helix of copper tape or copper wire2
Copper wire shield3
Inner insulation4
Cable core5
Selecting the control cables
￭ Shielding
Only use shielded control cables.
Use a double-shielded twisted pair cable for analog signals. This type of cable is
recommended for the pulse encoder signals also. Use one individually shielded pair for
each signal. Do not use common return for different analog signals.
68 Guidelines for planning the electrical installation
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