Fagor DDS Series, Hardware Manual

Page: 265 / 406

   Installation
8.
Ref.1912
· 265 ·
DDS
HARDWARE
Use equipotential wires in systems with:
MANDATORY .
Use shielded cables for power supply and motor.
On shielded cables, the unshielded portion of the cable used to connect them
to the connectors must be as short as possible in order to reduce radiated
emissions.
The motor encoder cable must have double-shield. Although the system
meets the current regulation regarding immunity using single-shielded cable,
the results are better when using double-shielded cables.
MANDATORY.
Installations of large areas.
Different voltage sources.
Mains through several buildings reducing the current in the cable shield and
the emissions. Connect to ground the electrical cabinet, the door, the
mounting plate, with ground straps or cables with a cross section larger than
10 mm² (AWG 6).
The ground shields of the digital signal wires must be connected at both
ends to a large surface or through a conductive housing of the connector.
This reduces disturbances that affect the signal cables and also the
emissions.
The ground shields of the analog signal wires must be connected directly to
the device (signal input), reducing the ground loops due to low frequency
disturbances.
When a unit does not have a ground connection, the shield must be
connected on the side of the unit connected to ground.
To connect large cable shield surfaces, use cable and ground clamps.
Run a single shielded cable, in one piece, without joints. If a cable must
necessary be cut for the installation, connect it with the shield connections
and through a metal cover at the cut (joint) point. In the worst case, if it is
not possible to use shielded connectors, keep a minimum length of cable
exposed to disturbances guaranteeing a good connection between the
shields. See figure
F. H8/3 . A .
Mount switching devices such as contactors, relays or electro-valves with
interference suppression elements or arc suppressors (e.g. diodes,
varistors, RC circuits).
Install power and control components separately.
Install before mains and the DDS system mains chokes to reduce harmonics
and expand the useful life of the product. EMC limit values may be improved
by also using external filters.
Use equipotential cables when having long lines to reduce the current
through the cable shield.
When connecting power cables, the shield of this cable should be connected
to a ground bar. See figure
F. H8/3 . B .
F. H8/2
A.
Make the shielded cables as short as possible when the connectors are
not shielded. B. Connection of the power cable shield to a bar that is connected
to ground.
A B