2 Engineering
2.4 EMC compliance
DC1 variable frequency drive 12/13 MN04020003Z-EN www.eaton.com 35
2.3.3 Mains contactors
The mains contactor enables an operational switching on and off of the
supply voltage for the variable frequency drive and switching off in case of a
fault.
The mains contactor is designed based on the mains-side input current I
LN
of
the variable frequency drive for utilization category AC-1 (IEC 60947) and the
ambient air temperature at the location of use. Mains contactors and their
assignment to the variable frequency drives belonging to the DC1 series are
listed in the annex ( Table 26, page 208).
2.4 EMC compliance
Electrical components in a system (machine) have a reciprocal effect on each
other. Each device not only emits interference but is also affected by it. This
occurs as a result of galvanic, capacitive and/or inductive coupling or through
electromagnetic radiation. In practice, the limit between line-conducted inter-
ference and emitted interference is around 30 MHz. At values above 30 MHz
the lines and cables act like antennas and radiate the electromagnetic waves.
Electromagnetic compatibility (EMC) for frequency controlled drives (variable
speed drives) is implemented in accordance with product standard IEC/EN
61800-3. This includes the complete power magnet system (PDS = Power
Drive System), from the mains supply to the motor, including all compo-
nents, as well as cables ( Figure 10, page 27). This type of magnet system
can consist of several individual drives.
The generic standards of the individual components in a magnet system
compliant with IEC/EN 61800-3 do not apply. These component manufac-
turers, however, must offer solutions that ensure standards-compliant use.
In Europe, maintaining the EMC Directive is mandatory.
A declaration of conformity (CE) refers always to a "typical" power magnet
system (PDS). The responsibility to comply with the legally stipulated limit
values and thus the provision of electromagnetic compatibility is ultimately
the responsibility of the end user or system operator.
Measures must be taken to remove or minimize emission in the associated
environment. He must also utilize means to increase the interference immu-
nity of the devices of the system.
￫
While planning the project, make sure that inching operation is
not done via the mains contactor of the variable frequency drive
on frequency-controlled drives, but through a controller input of
the variable frequency drive.
The maximum permissible mains voltage switch-on frequency
for the
DC1
variable frequency drive
is once every
30 seconds
(normal operation).
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