3 Installation
3.5 EMC installat ion
DA1 Variable Frequency Drives 11/16 MN04020005Z-EN www.eaton.com 85
3.5.2 Earthing
The protective earth (PE) in the control panel should be connected from the
mains supply to a central earth point (mounting plate, system earth).
The PE conductor’s cross-sectional area must be at least as large as that of
the incoming mains supply cable.
Every variable frequency drive must be individually connected to the power
supply system’s protective earth directly at the location of installation
(system earthing). This protective earth must not pass through any other
devices.
All protective conductors should be routed in a star topology starting from
the central earth point, and all of the magnet system’s conductive
components (e.g. variable frequency drive, sine filter) should be connected.
The earth-fault loop impedance must comply with all locally applicable
industrial safety regulations. In order to meet UL requirements, UL-listed ring
cable lugs must be used for all earth wiring connections.
3.5.2.1 Protective earth
This refers to the legally required protective earth for a variable frequency
drive. An earthing terminal on the variable frequency drive, or the system
earth, must be connected to a neighboring steel element in the building
(beam, ceiling joist), an earth electrode in the ground, or a mains earth bus.
The earth points must meet the requirements set forth by the applicable
national and local industrial safety regulations and/or regulations for electrical
systems.
3.5.2.2 Motor earthing
The motor earth must be connected to one of the earthing terminals on the
variable frequency drive and to a neighboring steel element in the building
(beam, ceiling joist), an earth electrode in the ground, or a mains earth bus.
3.5.2.3 Earth-fault protection
A fault current to earth can be produced by variable frequency drives due to
their system characteristics. DA1 series variable frequency drives have been
designed in such a way that the smallest possible fault current will be
produced in compliance with standards applicable worldwide. In the case of
devices powered with a three-phase supply (DA1-3…), this fault current
must be monitored by a residual current device (RCD, type B).
￫
Avoid
ground
loops
when
installing
multiple
variable frequency
drives in one control panel. Make sure that all metallic devices
that
are to be grounded have a broad area connection with the
mounting plate.
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