Grundfos NBE - EMC-Correct Installation

Related information
11.4 Electrical data
6.1.4 Motor protection
The motor requires no external motor protection. CUE protects the
motor against thermal overloading and blocking.
6.1.5 Protection against overcurrent
CUE has an internal overcurrent protection for overload protection
on the motor output.
6.1.6 Protection against mains voltage transients
CUE is protected against mains voltage transients according to EN
61800-3, second environment.
6.2 EMC-correct installation
The motor cable must be screened for CUE to meet EMC
requirements.
This section provides guidelines for good practice when installing
CUE. Follow these guidelines to meet EN 61800-3, first
environment.
• Use only motor and signal cables with a braided metal screen in
applications without output filter.
• There are no special requirements to supply cables, apart from
local requirements.
• Leave the screen as close to the connecting terminals as
possible. See figure Example of stripped cable with screen.
• Avoid terminating the screen by twisting the ends. See figure Do
not twist the screen ends. Use cable clamps or EMC screwed
cable entries instead.
• Connect the screen to frame at both ends for both motor
and signal cables. See figure Example of connection of a 3-
conductor bus cable with screen connected at both ends. If
the controller has no cable clamps, connect only the screen
to the CUE cabinet. See figure Example of connection of a
3-conductor bus cable with screen connected to CUE (controller
with no cable clamps).
• Avoid unscreened motor and signal cables in electrical cabinets
with frequency converters.
• Make the motor cable as short as possible in applications
without output filter to limit the noise level and minimise leakage
currents.
• Screws for frame connections must always be tightened
whether a cable is connected or not.
• Keep mains cables, motor cables and signal cables separated
in the installation if possible.
Other installation methods may give similar EMC results if the
above guidelines for good practice are followed.
TM021325
Example of stripped cable with screen
TM038812
Do not twist the screen ends
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English (US)