Lenze EDB9300UES - Manual (Page 86)

Transport, Installation and Connection
BA8230 81
•
Ideally the wiring should be divided into groups:
Power cables, power supply cables, analog signal leads, digital signal leads and
the bus or data leads.
Power cables and the signal and data leads should be placed in separate ducts or
bundles. Signal and data leads should preferably run close to grounded surfaces,
e.g. support beams, metal rails, mounting plates or cubicle panelling. These
measures are intended to suppress any “crosstalk” between parallel cables. Cables
which hang unsupported may act as passive or active antennas and can cause
interference.
Motor cables, mains supply cables and signal leads for the control electronics are
to be spaced at least 0.2 m apart inside the switchgear cubicle. This spacing can
be reduced where cables cross. Outside the switchgear cubicle the motor cables
should be laid in separate bundles spaced at a distance of at least 0.3 m - and
more when using longer parallel runs involving unscreened motor cables. No other
current circuits may be fed through or on the motor cable.
The following guidelines can be given as the minimum spacing (a) between parallel
screened signal leads and motor cables:
Up to 200 m a
≥
0.3 m
Up to 300 m a
≥
0.5 m
Up to 500 m a
≥
1.2 m
It is always better to use a separate metal cable track for laying control cables.
•
Signal leads for the control electronics and control cables outside the switchgear
cubicle are best laid on separate cable tracks to provide sufficient spacing to avoid
interference. If no separate cable track can be provided, signal leads are to be
partitioned off from power cables using chambers in the cable tracks and the
chamber are to be fitted with covers. Cables for processing the motor temperature
using thermistors are to be laid separately and never together with motor power
circuits.
•
Mains and motor cables are to be PVC insulated 3-phase cables according to DIN
VDE 0271 1986-06. If single conductors are used they should preferably be twisted
at 1 turn per 5 m and bundled in groups of three. If this is not the case, current
distribution may be disrupted and in extreme cases, in addition to cable
overloading, the drive system may malfunction.
•
Practical experience with EMC has shown that motor connection cables with
copper armouring or concentric corrugated protective conductors, for example
NYCWY (3-core) should be used. If the screen is connected in a low-impedance
configuration at both ends the screen sleeve / protective conductor guarantees
good attenuation to reduce the HF interference radiated from the motor cable
through high frequency recharging currents. The ground wiring should always have
the maximum possible cross-section. Steel armoured motor cables are unsuitable
for reasons of EMC.
•
To ensure a good EMC connection the motor cable at the frequency inverter side is
to be connected using pipe clamps, terminal clamps or screw connections which
surround the cable fully at the contact point to provide a good connection to the
screen bus or mounting plate.
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