3 Installation
3.4 Correct EMC installation
DB1 variable frequency drive
11/20 MN040031EN
Eaton.com
60
Figure 32: Separate routing
a
Power cable: Mains voltage, motor connection
b
Control and signal lines, fieldbus connections
3.4.2 Grounding
The protective ground (PE) in the control panel should be connected from the
mains supply to a central grounding point (mounting plate, system ground).
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 ground directly at the location of installation (sys-
tem grounding). This protective ground must not pass through any other
devices.
All protective conductors must be routed in a star-shaped layout extending
from the central grounding point, and all of the drive system's conductive
components must be connected.
The ground loop impedance must comply with all locally applicable industrial
safety regulations. In order to meet UL standards, UL-listed ring cable lugs
must be used for all ground wiring connections.
3.4.2.1 Protective ground
This refers to the legally required protective ground for a variable frequency
drive. A grounding terminal on the variable frequency drive, or the system
ground, must be connected to a neighboring steel element in the building
(beam, ceiling joist), a ground electrode in the ground, or a mains ground bus.
The ground points must meet the requirements set forth by the applicable
national and local industrial safety regulations and/or regulations for electrical
systems.
a
b
a
b
￫
Avoid ground loops when installing multiple variable frequency
drives in a single control panel. Make sure that all metallic
devices that are to be grounded have a broad area connection
with the mounting plate.