NORD Drivesystems BU0135 - Manual (Page 23)

2 Assembly and installation
BU 0135 GB-2713 Pre-series version 23
2.3 Wiring guidelines
The motor starters have been developed for use in an industrial environment. In this environment, high lev-
els of electromagnetic interference can influence the motor starter. In general, correct installation ensures
safe and problem-free operation. To meet the limiting values of the EMC directives, the following instruc-
tions should be complied with.
(1) Ensure that all equipment in the control cabinet or field is securely earthed using short earthing cables
which have large cross-sections and are connected to a common earthing point or earthing rail. It is
especially important that all control devices connected to the motor starter (e.g. an automation device)
are connected to the same earthing point as the motor starter itself, using a short cable with large
cross-section. Flat conductors (e.g. metal clamps) are preferable, as they have a lower impedance at
high frequencies.
(2) The bonding cable of the motor controlled by the motor starter should be connected directly to the
earthing terminal of the associated motor starter. The presence of a central earthing bar in the control
cabinet and the grouping together of all bonding conductors to this bar normally ensures safe
operation. (See also Section 7.3 / 7.4(EMC))
(3) Where possible, shielded cables should be used for control circuits. The shielding at the cable end
should be carefully sealed and it must be ensured that the wires are not laid over longer distances
without shielding.
(4) The control cables should be installed as far as possible from power cables, using separate cable
ducts, etc. Where cables cross, an angle of 90° should be ensured as far as possible.
(5) Ensure that the contactors and brake chokes in the cabinet are interference protected, either by RC
circuits in the case of AC contactors, or by “free-wheeling” diodes for DC contactors, whereby the
interference protectors must be positioned on the contactor coils. Varistors for over-voltage
limitation are also effective.
In addition, an EMC-compliant cabling must be ensured. (See also Section 7.3 / 7.4 (EMC)).
The safety regulations must be complied with under all circumstances
when installing the motor starter!
NOTE
The control cables, mains cables and motor cables must be laid separately. In no
circumstances should they be laid in the same protective pipes/installation ducts.
The test for high voltage insulations must not be used on cables which are connected to the
motor starter.
ATTENTION
With the use of a ParameterBox SK PAR-3H this must never be simultaneously connected to
the motor starter and the PC, as potential shifts may cause damage, especially to the PC.
(See also Manual BU0040)