Mechanical Installation; Emc-Correct Installation - Grundfos CU 3 Serie Instrucciones De Instalación Y Funcionamiento

5. Mechanical installation

Fasten the CU 3X2 with the four screws, M5 x 10,
supplied with the unit (pos. 1).
Maximum torque: 1.4 Nm.
Dimensions of the CU 3X2, see section
14. Dimensions.
Min. 1.5 mm
Max. 3 mm
Fig. 7 Mounting in panel front (standard)
In order to achieve enclosure class IP55,
Note
the CU 3X2 must be mounted in a panel or
cabinet.
Connect the earth terminal (between the cable
clamps) on the CU 3X2 to the mounting frame
(pos. 2, fig. 7). See fig. 8.
Fig. 8 Earth connection

6. EMC-correct installation

The CU 3X2 is normally mounted in a panel which
also contains an IO 351 module, contactors and
other power equipment. The panel can also contain
other Grundfos modules and frequency converters.
In order to ensure faultless operation, it is very
important to install the electronic modules in an
EMC-correct way:
• Ensure a sufficient earth connection between the
CU 3X2 and the frame. See fig. 8.
• Use screened cables for GENIbus. Connect the
screen to the cable clamp of the CU 3X2 in front
of the terminals A1, Y1 and B1. See fig. 9.
Also use screened cable for the CIM module.
Fig. 9 Screen fixed with cable clamp
Any isolating plastic tape between screen
Note
and sheath must be removed before
mounting the cable in the cable clamp.
• Signal conductors for digital and analog inputs
and outputs should be screened, i.e. run the
screen all the way to the CU 3X2 and connect it
to frame with for instance a cable clamp.
Do not twist screen ends to avoid pig tails, as this
will destroy the screen effect at high frequencies.
Use cable clamps instead.
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