Operating instructions

6-32 Mounting and Installation Rexroth IndraDrive
DOK-INDRV*-FU*********-IB01-EN-P
Ground Connections
By means of appropriate ground connections it is possible to avoid the
emission of interference, because interference is discharged to earth on
the shortest possible way. Ground connection of the metal housings of
EMC-critical components such as filters, devices of the drive system,
connection points of the cable shields, devices with microprocessor and
switching power supply units have to be over a large surface area and
well contacted. This also applies to all screw connections of between
mounting plate and control cabinet wall and to the mounting of a ground
bus to the mounting plate.
For this purpose it is recommended to use a zinc-coated or chromatized
mounting plate. Compared to a lacquered plate, the connections in this
case have a good long-time stability.
For lacquered mounting plates always use screw connections with tooth
lock washers and zinc-coated, tinned screws as connection elements. At
the connection points selectively scratch off the lacquer so that there is
safe electrical contact over a large surface area. Contact over a large
surface area is established by means of bare connection surfaces or
several connection screws. For screw connections the contact to
lacquered surfaces is ensured by using tooth lock washers.
In any case use connection elements with good electroconductive
surface.
Bare zinc-coated, tinned and chromatized metal surfaces have good
electroconductive properties. Anodized, yellow chromatized, black
gunmetal finish or lacquered metal surfaces have bad electroconductive
properties and therefore shouldn't be used for connection elements
(screws, nuts, plain washers).
For connecting ground wires and shield connections it is not the cross
section but the size of contact surface that is important, as the high-
frequency interference currents mainly flow on the surface of the
conductor.
Any connection of cable shields, especially of shields of the motor power
cables with ground potential (see section "Connection of Motor Cable to
Drive Controller") always has to be provided over a large surface area.
Housing and Mounting Plate
Connection Elements
Metal Surfaces
Ground Wires and Shield
Connections