An overview of the EMC
Frédéric Pythoud, Head of the EMC Laboratory
Outline
Scientific aspects
(Physics)
Legal aspects
(Regulation)
2
3
EMC
(Electromagnetic
compatibility)
Practical aspects
(Test methods,
infrastructure,
modifications) 5
1
Technical aspects
(Technical standards)
4
Questions
6
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1. What is EMC ?
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1.1 What is electromagnetic non-compatible
The mobile phone might
disturb a electric/electronic
equipment
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1.2 Which goal is desired ?
Customer expectations:
electrical devices should not disturb themselves
Legal aspects
Technical aspects
Practical aspects
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1.3 EMC is important
A West GermanTornado fighter crashed after flying too close to a powerful
transmitter. (1984)
A foundry worker died when the radio-controlled overhead transporter thought
out a few tons of liquid metal on him.
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2. Scientific aspects
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2.1 Electromagnetic field
Electromagnetic wave propagate likes waves
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2.2 Maxwell’s equations


H
rot E   
 t

E 
rot H  
j
t

  div E  

Equations
 

 

div H  0
James Clerk Maxwell (1831–1879)
Faraday’s induction law
Ampere-Maxwell law
Electrostatic law
Equation of Magnetismus
Time dependence
Solution
Retarded magnetic
vector potential
 
A
4

currents
distances

 
j r , t  r   r c 
d
 
r r


 rot A
H

   
 1
 
E   rot H  j dt

t
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2.3 Interpretation
i1
E
i2
Electric currents
H
Electromagnetic
Waves
Electric currents
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2.4 Examples
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2.5 Practical example
Shield
« Abschirmung »
currents
230 V
control
cable
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2.6 Example of a solution
Shield
« Abschirmung »
Optical
control
cable
Other possibility
use filters
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3. Regulation aspects
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3.1 Which requirements must be fulfilled
Legal aspects
EU - Directive
CH-Verordnung
Technical standards:
Technical
aspects
EN, IEC, CISPR, ETSI, ISO
Practical aspects
Construction / EMC Testing
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3.2 The EU directives
http://ec.europa.eu/growth/single-market/european-standards/harmonisedstandards/index_en.htm
EMC requirements
EMC requirements
EMC requirements
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3.3 EMC Directive
EMC Directive 2004/108 EC (15 December 2004)
New EMC Directive 2014/30/EU (26 February 2014)
applicable from 20 April 2016
ANNEX I
ESSENTIAL REQUIREMENTS
1. General requirements
Equipment shall be so designed and manufactured, having regard to the state of the art,
as to ensure that:
Emission
(a) the electromagnetic disturbance generated does not exceed the level above which
radio and telecommunications equipment or other equipment cannot operate as
intended;
Immunity
(b) it has a level of immunity to the electromagnetic disturbance to be expected in its
intended use which allows it to operate without unacceptable degradation of its intended
use.
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3.4 Two requirements for electronic devices
Immunity
A device shall be
immune to electromagnetic disturbances
Emission
A device shall not
emit too much
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3.5 More information in the essential requirements
(b) it has a level of immunity to the electromagnetic disturbance to be
expected in its intended use which allows it to operate without
unacceptable degradation of its intended use.
1. it has a level of immunity
2. to the electromagnetic disturbance to be expected in its intended use
3. which allows it to operate without unacceptable degradation
4. of its intended use.
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3.6 Acceptance that immunity is not «infinite»
Immunity to
electromagnetic
fields
is like water proof:
it is always limited
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3.7 For which environment ?
 EMC tested
Correct statement would be
 EMC tested for industry applications
 EMC tested for automotive applications
 EMC tested for household applications
 EMC tested for … hospital applications
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3.8 What are acceptable degradations ?
 How wrong is acceptable ?
• 1g?
• 5g?
• 10 g ?
 It depends on the product
specification (declaration
of the manufacturer)
 It depends on the use:
- precision device
- household device
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3. Technical aspects
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4.1 How these requirements are
translated into tests
First step: identification of the possible, realistic disturbance
sources (example of immunity)
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4.2 Model of the disturbance via a standard test
 IEC 61000-4-2
Test according to IEC 61000-4-2
simulate:
Electrostatic discharge cause by
walk on a carpet
 IEC 61000-4-3
Test according to IEC 61000-4-3
simulate:
Disburbance from RF transmitters
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4.3 Model of the disturbance via a standard test
 IEC 61000-4-4
Test according to IEC 61000-4-4
simulate:
Disturbance from motors,
fluorescent tubes, …
 IEC 61000-4-5
Test according to IEC 61000-4-5
simulate:
Disturbance from lightning
123rf.com: Image ID : 8201642
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4.4 Model of the disturbance via a standard test
 IEC 61000-4-6
Test according to IEC 61000-4-6
simulate:
Disturbance from radio
transmitters
 IEC 61000-4-11
Test according to IEC 61000-4-11
simulate:
Disturbance from
the mains (230 V)
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4.5 Overview
EU - Directive
Customer
expectations
CH-Verordnung
Household Devices
IEC/EN 61000-6-1
IEC/EN 61000-6-3
IEC/EN 61000-4-2
CISPR 16
Industry Devices
IEC/EN 61000-6-2
IEC/EN 61000-6-4
IEC/EN 61000-4-3
IEC/EN 61000-3-2
Multimedia Devices
CISPR 32
IEC/EN 61000-4-39
IEC/EN 61000-3-3
Product standard
(provide the test,
test level and criteria)
Basic Standards
(describe
the test itself)
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4.6 Performance Criteria also defined in the
standard
 Performance criterion A: The apparatus shall continue to
operate as intended (during the test)
 Performance criterion B: The apparatus shall continue to
operate as intended after the test.
 Performance criterion C: Temporary loss of function is
allowed, provided the function is self-recoverable
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5. Practical aspects
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5.1 Testing requires an infrastructure









EMC chamber
Pulse generators
Antenna
Measuring receivers
Amplifiers
Coupling-Decoupling networks
Current clamps
Common mode absorbing clamps
…
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5.2 Test must represent the reality
Device under test
may have several
states:
-produce coffee
-idle
Important: Devices
should be equiped
with special test
mode commands.
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5.3 Corrective actions











Use of filters
Use of common mode rejection ferrites
Correct earthing
Improvement of the shielding
Improvement of the cabling
Modification of the powering
Modification of components
…
Software corrections
…
Redesign of the print
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6. Summary
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6.1 Questions
 Is a successfully tested product conform to the EMC directive ?
 Is a product that was never tested, conform to the directive ?
 Can a product be brought on the market without emc testing ?
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6.2 In Summary
Scientific aspects
(Physics)
Legal aspects
(Regulation)
EMC
(Electromagnetic
compatibility)
Practical aspects
(Test methods,
infrastructure,
modifications)
Technical aspects
(Technical standards)
Literature
• Adolf J. Schwab, « Elektromagnetische Verträglichkeit », Springer Verlag, 1990.
•http://wireless.ictp.it/school_2005/lectures/struzak/Introd_to_EMC.pdf
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Thank you very much for your attention