Basic Information About Emc; Introduction To Emc; Interference And Noise Immunity - Siemens SINAMICS S120 Equipment Manual

Cabinet Design and EMC

7.2 Basic information about EMC

7.2 Basic information about EMC
7.2.1

Introduction to EMC

EMC stands for "electromagnetic compatibility" and, according to the definition in the
Directive, describes "the capability of a device to function satisfactorily in an electromagnetic
environment without itself causing interference unacceptable for other devices in the
environment.."
EMC, therefore, represents a quality standard for the following:
• Internal noise immunity: Resistance to internal electrical disturbances
• External noise immunity: resistance against external electromagnetic disturbances
• Emitted interference: environmental effects caused by electromagnetic emissions
To ensure that the chassis unit functions satisfactorily in the system, the environment subject
to interference must also be taken into consideration.
7.2.2

Interference and noise immunity

The EMC depends on two aspects of the devices in question: interference and noise
immunity. Electrical devices include noise sources (transmitters) and potentially susceptible
equipment (receivers). A device can be both a noise source (power section of a converter)
and potentially susceptible (control section of a converter) at the same time. Electromagnetic
compatibility is ensured when the existing noise sources do not impair the function of
potentially susceptible equipment.
Measures must be taken by the converter manufacturer and the operator to ensure the
greatest possible level of operational reliability and noise immunity within the entire system
(converters, automation systems, drive motors, and so on). Only when all of these measures
have been taken are the satisfactory function of the converter and compliance with the legal
requirements (89/336/EEC) ensured.
Interference from frequency converters is covered by European standard EN 61800-3,
whereby conducted interference on the line connection is measured as a radio interference
voltage under standardized conditions. Radio interference emission in the form of
electromagnetic emissions. The standard defines limit values for "environment 1" (public
networks) and "environment 2" (industrial networks).
Noise immunity describes the behavior of a device under the influence of electromagnetic
interference. Product standard EN 61800-3 outlines the EMC requirements for "variable-
speed drive systems". It specifies requirements for converters with operating voltages of less
than 1000 V. Different environments and categories are defined depending on where the
system is installed.
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SINAMICS S120 Equipment Manual, Edition 12/2007, 6SL3097-2AM00-0BP4
Chassis Power Units Liquid Cooled