Baumuller BUM 62 T, User Manual

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Installation
28
Mono Power Unit BUM 62 T
5.99009.03
Baumüller Nürnberg GmbH
Grounding
y To meet EMC requirements, the classical star grounding is no longer sufficient to reduce the noise
of high frequencies caused by converter operation. Better results can be achieved by a reference
surface which must be linked to the units’ ground (e.g. bare metal mounting plate and housing parts).
y If a large reference surface is not possible the main equipotential bonding strip should be arranged
directly at the power unit which generates the largest potential steps compared to the other
components in the switch cabinet (ground connection < 50 cm if possible).
y To avoid earth loops, apply all ground connectors and screens as close as possible above the
ground.
y If it is possible to ground the controller reference potential of the power unit, make the connection
with as large a cross-section as possible and a short cable (<50 cm).
y Remove insulating layers such as paint, adhesives, etc. from the ground connections. If necessary,
use serrated lock washers (DIN 6798) or similar measures to ensure a permanent, conductive
contact. To prevent corrosion on ground connections, use suitable metal combinations
(electrochemical series of metals) and keep conductive electrolytes away from the connection by a
protective coating (e.g. grease).
y Always connect screens at both ends over a large surface and conductive to ground. This is the only
way to suppress the effects of magnetic or high-frequent noise. If earth loops occur (e.g. double
insulation of the setpoint conductor screen), apply the receiver side galvanically and the transmitter
side capacitively.
y When laying external cable screens through panels separating different EMC areas, make contact
to the cable screens.
Cables which are passed through the panels of screening housings without special measures (e.g.
filtering), may impair the screening effect of these housings. For this reason, you must make a
conductive connection of the cable screens at the point at which the cable enters the housing.
The distance of the last screen contact point to the exit of the cabinet must be as short as possible.