Goodrive200A
inverters Appendix C
146
recommended. Compared to a four-conductor system, the use of a symmetrical shielded
cable reduces electromagnetic emission of the whole drive system as well as motor bearing
currents and wear.
Note:
A separate PE conductor is required if the conductivity of the cable shield is not
sufficient for the purpose.
To function as a protective conductor, the shield must have the same cross-sectional area as
the phase conductors when they are made of the same metal.
To effectively suppress radiated and conducted radio-frequency emissions, the 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. The
better and tighter the shield, the lower the emission level and bearing currents.
C.4.2 Control cables
All analog control cables and the cable used for the frequency input must be shielded. Use a
double-shielded twisted pair cable (Figure a) for analog signals. Employ one individually
shielded pair for each signal. Do not use common return for different analog signals.
A double-shielded cable is the best alternative for low-voltage digital signals, but a
single-shielded or unshielded twisted multi-pair cable (Figure b) is also usable. However, for
frequency input, always use a shielded cable.
The relay cable needs the cable type with braided metallic screen.
The keypad needs to connect with cables. It is recommended to use the screen cable on
complex electrical magnetic condition.
Note: Run analog and digital signals in separate cables.
Do not make any voltage tolerance or insulation resistance tests (for example hi-pot or
megger) on any part of the drive as testing can damage the drive. Every drive has been
tested for insulation between the main circuit and the chassis at the factory. Also, there are
voltage-limiting circuits inside the drive which cut down the testing voltage automatically.
Check the insulation of the input power cable according to local regulations before
