Siemens 1FK6 Instrucciones De Servicio página 192

Installation in Conformance with EMC Regulations
Rule 9
Rule 10
Rule 11
Rule 12
Rule 13
Rule 14
6-2
The cable shields of digital signal cables must be connected to ground
at both ends (transmitter and receiver) through the largest possible
surface area. If the equipotential bonding is poor between the shield
connections, an additional equipotential bonding conductor with at least
10 mm² must be connected in parallel to the shield, to reduce the shield
current. Generally, the shields can be connected to ground (= cabinet
housing) in several places. The shields can also be connected to
ground at several locations, even outside the cabinet.
Foil-type shields are not to be favoured. They do not shield as well as
braided shields; they are poorer by a factor of at least 5.
The cable shields of analog signal cables can be connected to ground
at both ends if the equipotential bonding is good. Good equipotential
bonding is achieved if Rule 1 is observed.
If low-frequency noise occurs on analog cables, for example:
speed/measured value fluctuations as a result of equalizing currents
(hum), the shields are only connected for analog signals at one end at
the SIMOVERT MASTERDRIVES. The other end of the shield should
be grounded through a capacitor (e.g. 10 nF/100 V type MKT).
However, the shield is still connected at both ends to ground for high
frequency as a result of the capacitor.
If possible, the signal cables should only enter the cabinet at one side.
If SIMOVERT MASTERDRIVES are operated from an external 24 V
power supply, this power supply must not feed several consumers
separately installed in various cabinets (hum can be coupled-in!). The
optimum solution is for each SIMOVERT MASTERDRIVE to have its
own power supply.
Prevent noise from being coupled-in through the supply.
SIMOVERT MASTERDRIVES and automation units/control electronics
should be connected-up to different supply networks. If there is only
one common network, the automation units/control electronics have to
be de-coupled from the supply using an isolating transformer.
The use of a radio interference suppression filter is obligatory to
maintain limit value class "First environment" or "Second environment",
even if sinusoidal filters or dv/dt filters are installed between the motor
and SIMOVERT MASTERDRIVES.
Whether an additional filter has to be installed for further consumers,
depends on the control used and the wiring of the remaining cabinet.
6SE7087-8JP50
Operating Instructions SIMOVERT MASTERDRIVES
02.2008
Siemens AG