Siemens SIMOVERT MASTERDRIVES Manual page 46

Instructions for Design of Drives in Conformance with EMC Regulations
3.2 Principles of EMC
3.2.1 What is EMC?
3.2.2 Noise emission and noise immunity
3-2
EMC stands for "ElectroMagnetic Compatibility" and, in accordance
with the EMC Law §2(7), it defines "the capability of a unit to operate
satisfactorily in an electromagnetic environment, without itself causing
electromagnetic disturbances which would be unacceptable for other
electrical units in this environment".
In principle, this means that units should not interfere with each other.
And this is a feature that you have always looked for in your electrical
products!
EMC is dependent on two characteristics of the units concerned - the
emitted noise and the noise immunity. Electrical equipment can either
be treated as a noise source (transmitter) and/or a noise receiver.
Electromagnetic compatability exists when the existing interference
sources do not affect the function of the noise receivers. It is also
possible for a unit to be both an interference source and an interference
receiver at the same time. For example, the power section of a
frequency converter can be regarded as a noise source, whereas the
control section can be regarded as a noise receiver.
The noise emission of frequency converters is governed by the
European Standard EN 61800-3. The cable-related noise at the mains
connection is measured under standard conditions as radio interference
voltage. Electromagnetically emitted noise is measured as radio
interference (radiated noise). The standard defines limit values "First
environment" (public supply networks) and "Second environment"
(industrial networks).
When the equipment is connected up to the public supply, the
maximum harmonics specified by the local power supply company must
be observed.
The noise immunity of a unit describes how it behaves when
subjected to electromagnetic noise/interference. The requirements and
evaluation criteria for the behaviour of the electrical units are also laid
down in standard EN 61800-3.
6SE7087-6QX70 (Version AD)
Compendium Motion Control
05.2003
Siemens AG
SIMOVERT MASTERDRIVES