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TRANSCRIPT
EMC TESTING
Jorge BERKOWITSCH
Chapter 1. Introduction to EMC
Chapter 2. EMC Concepts
Chapter 3. Standardisation
Chapter 4. EMC testing - COMMERCIAL sector
Introduction to EMC
Electromagnetic Compatibility means the ability of equipment to function satisfactorily in its electromagneticenvironment without introducing intolerable electromagnetic disturbances to other equipment in that environment.
Electromagnetic environment means all electromagnetic phenomena observable in a given location.
Electromagnetic disturbance means any electromagnetic phenomenon which may degrade the performance ofequipment. An electromagnetic disturbance may be electromagnetic noise, an unwanted signal or a change in thepropagation medium itself.
Immunity (Susceptibility) means the ability of equipment to perform as intended without degradation in the presenceof an electromagnetic disturbance
Definitions
Introduction to EMC
Classification of phenomena
Wanted signal
Unwanted signal
Interference
Sources
From transmitter
Interference Sources
Introduction to EMC
The Hindemburg disaster - Thursday, May 6, 1937
A spark had ignited leaking hydrogen. However what was the cause of the spark or leak?:
1. A sabotage2. A lightning strike3. An electrostatic discharge
The third option has been chosen as the most likely cause. The German airship had become charged with static asa result of an electrical storm. A broken wire or sticking gas valve leaked hydrogen into the ventilation shafts, andWhen Ground crew members ran to take the landing ropes they effectively “earthed” the airship. The fire appearedon the tail of the airship, igniting the leaking hydrogen.
Real Life EMC problems – Air navigation
Introduction to EMC
U.S.S. Forrestal incident - 1967
In the Gulf of Tonkin on 29 July, Forrestal had been launching aircraft from her flight deck. For four days, thePlanes of Attack Carrier Air Wing 17 flew about 150 missions against targets in Northh Vietnam from the ship.On 29 July 1967, during preparation for another strike, a Zuni rocket installed on an F-4 Phantom, misfired, impacting an armed A-4 Skyhawk, parked on the port side. The rocket's impact dislodged and ruptured theSkyhawk's 400-gallon external fuel tank. Fuel from the leaking tank caught fire, creating a serious conflagrationthat burned for hours, killing 134, injuring 161, destroying 21 aircraft and costing the Navy US$72 million.
The accidental firing is believed to have been triggered by a combination of the powerful fields at deck level from the ship’s radar and an incorrectly fitted shielded cable connector.
Real Life EMC problems - Military
Introduction to EMC
The sinking of of H.M.S. Sheffield during the Falkland/Malvinas Islands War – 4th May 1982
The HMS Sheffield was a Type 42 guided missile destroyer and was fitted with the Type 965 radar system. This wasan old system that was due to be upgraded to the Type 1022 system. Two Argentine Navy Super Étendards (3-A-202and 3-A-203) both armed with Exocets fired two missiles and one of them hit the HMS Sheffield
The Sheffield’s search radar was switched off when the satellite communication system was used, because ofinterference from the radar. Without its search radar the Sheffield’s anti-missile defences could not be used, and thisallowed an Exocet missile to hit the ship on 4th May 1982.
Real life EMC problems - Military
Introduction to EMC
Black Hawk helicopter – 1987
While flying past a radio broadcast tower in West Germany, a U.S. Army Sikorsky UH-60 Blackhawk helicopterexperienced an uncommanded stabilator movement. Subsequent investigation showed that the stabilator systemwas affected by EMI.
Between 1981 and 1987, five Blackhawk helicopters flying too near radio transmitters crashed killing or injuring allon board. The Navy version of the Blackhawk, the SB-60 Seahawk was hardened against the severe EM environmentsof ships and did not experience the same EMI problems as the Blackhawk.
Real life EMC problems - Military
Introduction to EMC
1994 - FDA Advises Wheelchair Manufacturers to Warn Users about Interference from Cell Phones and otherdisturbance sources
In response to reports of electric wheelchairs that spontaneously engaged as a result of interference from cell phonesor other sources (trams), the U.S. Food and Drug Administration issued an advisory recommending that pacemakerWearers not carry cell phones in their shirt pockets.
Some powered wheelchairs experimented erratic unintentional movements near cell phones or trams. These movementsincluded sudden starts that caused to wheelchairs to drive off curbs of piers. No fatal injuries have been reported.However the FDA has ordered to wheelchairs manufacturers to improve shielding and add warnings to their products toProtect from EMI
Real life EMC problems – Medical devices
Introduction to EMC
TWA Flight 800 crashes - 1996
On July 17, 1996, TWA Flight 800, a Boeing 747 bound for Paris, exploded shortly after takeoff from New York's JFKInternational airport, killing all 230 people on board. The National Transportation Safety Board concluded that the probable cause of the accident was an "explosion of the center wing fuel tank" resulting from an ignition of the fuel/airmixture inside the tank.
The likely source of the ignition was an arc generated in the wiring associated with the fuel quantity indication system.
Real life EMC problems - Aircraft
Introduction to EMCElements of an EMC phenomenon
Coupling pathDisturbanceSource
Receiver orvictim
Solar radiation,LightningArc welding equipmentRF transmittersElectrical motorsHigh speed tracksVDU, clocks…
Air - antennasPower supply cordsInterconnection cablesCommon earthParasitic capacitancesParasitic Inductances
RF receiversICsElectronic controlsHigh speed tracksPhone setsCPU…
How to attenuate or eliminate the disturbance?
EMC Concepts
Emissions
EMC Concepts
Immunity - Susceptibility
EMC Concepts
Intersystem disturbances for commercial equipment
EMC Concepts
Intrasystem disturbances for commercial equipment
EMC Concepts
Commercial requirements Radiated Emissions
Conducted emissions
Harmonics
Flickers
Radiated immunity
ESD
EFT/Bursts
Surges
Conducted immunity
Voltage dips, short interruptions and voltage variations
EMC Concepts
EMC Control
EMC Concepts
EMC levels
EMC Concepts
Far field
3771200
00
HEZ
Electromagnetic waves consist of two orthogonal fields and are placed onplanes orthogonals to the propagation direction. So, they are trasnsversalwaves or fields
E-field (V/m) and H-field (A/m) are orthogonals between them and the waveimpedance is defined as
Propagation is according to
EMC Concepts
Near field
EMC Concepts
Near field – Far field
Propagation depending of wave impedance
EMC Concepts
Near field – Far field under Rayleigh criterion
EMC Concepts
Time vs Frequency
Time domain Waveform
Slew rate
Rise time
Fall time
Frequencu domain Spectrrum
Harmonivs
Fourier transform
Inverse Fourier transform
Standardization
Type of standards
Civil Stds.
Military Stds
International: IEC, CIPR, ISO…
European: EN, ETSI…
National: UNE-EN, BS, NF, VDE, ANSI, VCCI….
Basic Standards
Generic Standards
Product Standards
Famiyi product standards
Standardization
European standards – Regulatory framework
Standardization
European normes - EN
Harmonized standards are those issued within the OJEU
Summary list of titles and references harmonised standards under Directive 2004/108/EC for Electromagnetic compatibility (EMC): http://ec.europa.eu/enterprise/policies/european-standards/harmonised-standards/electromagnetic-compatibility/index_en.htm
European Norme generation:
The number comes from the organization
CISPR EN 55XXX IEC EN 61000-X-X
CISPR 22 EN 55022 UNE-EN 55022
IEC 6100-4-3 EN 61000-4-3 UNE-EN 61000-4-3
EMC testing – Commercial sector
General
EMC testing – Commercial sector
Radiated disturbances – Measurement site a) Test site b) alternative test site
EMC testing – Commercial sector
Radiated disturbances – Measurement site Semianechoic chamber
EMC testing – Commercial sector
Radiated disturbances – Measurement site Semianechoic chamber calibartion: NSA measurement
Typical antenna positions for alternate site NSA measurements
Vertical polarization Horizontal polarization
EMC testing – Commercial sector
Radiated disturbances – Measurement site Semianechoic chamber calibartion: NSA measurement
Typical antenna positions for alternate site NSA measurements for minimum recommended volume:1 m depth, 1.5 m witdht and 1.5 height
Vertical polarization Horizontal polarization
EMC testing – Commercial sector
Radiated disturbances – Measuring equipment
Antenna bilog Log-per antenna radiation pattern
Antennas
Linear polarized antennas: dipole, biconnical, log-per, bilog and horns
Biconnical antenna
EMC testing – Commercial sector
Emission interferences – Measuring equipment
Receivers or spectrum analyzers in accordance with EN 55016-1-1
Receivers Spectrum analyzer
Preselector + QP adapter
EMC testing – Commercial sector
Emission interferences – Measuring equipment
AMN, LISN and ISN
Supplies the necessary mains voltage (AC or DC) and current for the EUT,Couples interference voltage generated by the EUT and supplies it to the measuring equipment, Well defined impedance to the EUT: 50 Ω/50 µH , 50 Ω/5 µH or 150 Ω , Acts as filter, keeping away unwanted disturbances coming from mains
EMC testing – Commercial sector
Emission interferences – Measuring equipment
AMN, LISN and ISN impedance
EMC testing – Commercial sector
Emission interferences – Type of measurements
Peak Average Quasi-peak
1
2
t2 t1
A/3
A
EMC testing – Commercial sector
Emission interferences – Limits
EMC testing – Commercial sector
Radiated disturbances – Limit class A
Radiated disturbances – Limit class B
EMC testing – Commercial sector
Radiated disturbances – Limit class A
Radiated disturbances – Limit class B
EMC testing – Commercial sector
Radiated disturbances – General test set-up
EUT
Antenna
3 or 10 m
EMC testing – Commercial sector
Radiated disturbances – General test set-up
EUT
Turntable
Receiver
1 to 4 m
EMC testing – Commercial sector
Radiated disturbances – Test arrangement for tabletop equipment (top view)
EUT
EMC testing – Commercial sector
Radiated disturbances – Test arrangement for tabletop equipment
EUT
EMC testing – Commercial sector
Radiated disturbances – Test arrangement for floor-standing equipment
EUT
EMC testing – Commercial sector
Radiated disturbances – Test arrangement for combinations of equipment
EUT
EMC testing – Commercial sector
Radiated disturbances – Results
0
10
20
30
40
50
60
70
80 Level [dBµV/m]
30M 40M 50M 70M 100M 200M 300M 400M 600M 1GFrequency [Hz]
x xx
xx
xx
x
EMC testing – Commercial sector
Radiated disturbances – Results
EUT
EMC testing – Commercial sector
Conducted disturbances – Mains terminals (AC or DC). Limit class A
EUT
Conducted disturbances – Mains terminals (AC or DC). Limit class B
EMC testing – Commercial sector
Conducted disturbances – Telecommunication ports. Limit class A
EUT
Conducted disturbances – Telecommunication ports. Limit class B
EMC testing – Commercial sector
Conducted disturbances – Test arrangement for tabletop equipment (top view)
EUT
EMC testing – Commercial sector
Conducted disturbances – Test arrangement for tabletop equipment. Alternative 1a
EMC testing – Commercial sector
Conducted disturbances – Test arrangement for tabletop equipment. Alternative 1b
EMC testing – Commercial sector
Conducted disturbances – Test arrangement for tabletop equipment. Alternative 2
EMC testing – Commercial sector
Conducted disturbances – Test arrangement for floor-standing equipment
EMC testing – Commercial sector
Conducted disturbances – Test arrangement for combinations of equipment
EMC testing – Commercial sector
Conducted disturbances on telecomm lines – Voltage or currente measurementat balanced telecommunication ports intended for connection to unscreenedbalanced pairs
Using CDNs or ISNs of EN including those described in EN 61000-4-6
1) Distance to the reference ground plane (horizontal or vertical)
2) Distance to the reference ground plane is not critical
EMC testing – Commercial sector
Conducted disturbances on telecomm lines – Voltage or current measurementat telecommunication ports intended for connection to screened cables or coaxial cables
Using a 150 Ω load to the outside surface of the shield
1) Distance to the reference ground plane (horizontal or vertical)
2) Distance to the reference ground plane is not critical
As previous slide or using the following set-up
EMC testing – Commercial sector
Conducted disturbances on telecomm lines – Voltage or current measurementat telecommunication ports intended for connection to cables containing more than four balanced pairs or to unbalanced cables. Version 1
1) Distance to the reference ground plane (horizontal or vertical)
2) Distance to the reference ground plane is not critical
Using a combination of current probe and capacitive voltage probe
EMC testing – Commercial sector
Conducted disturbances on telecomm lines – Current measurement attelecommunication ports intended for connection to cables containing more than four balanced pairs or to unbalanced cables. Version 2
1) Distance to the reference ground plane (horizontal or vertical)
2) Distance to the reference ground plane is not critical
Using no shield connection to ground and no ISN
EMC testing – Commercial sector
Conducted disturbances on mains terminals - Results
EMC testing – Commercial sector
Conducted disturbances on telecommunication ports - Results
EMC testing – Commercial sector
Harmonics – Introduction
In general the public mains power supply voltage waveform is sinusoidal, which means that it includes only thefundamental frequency (50 or 60Hz), without any harmonic multiples of this frequency. Purely resistive circuits suchas filament lamps or heaters, when powered from the mains, draw a current that is directly proportional to the appliedvoltage, and do not create any extra harmonic components. By contrast, non-linear circuits do draw a non-sinusoidal current, despite the applied voltage being sinusoidal. Examples of non-linear loads include:
• fluorescent lamps and phase-angle-controlled lamp dimmers;• the DC power supplies of any electronic product, whether linear or switch-mode;• three-phase power converters;• arc welding, electric furnaces, electrolytic processes, and other industrial applications
Single phase mains – Typical waveform Three phase mains – Typical waveform
EMC testing – Commercial sector
Harmonics – Problems The main problem with the harmonic currents is that they can cause overheating in the local supply distribution
transformer if it is inadequately rated, or if it is rated on the assumption of low harmonic levels. Power factor correction capacitors can overheat as well, due to the much higher harmonic currents they experience because of their lower impedance at higher frequencies, leading to failure
Harmonic currents in the Neutral conductors of three-phase supplies present reliability and safety risks, where Neutral conductors have not been suitably dimensioned. Many older buildings are known to use half-size or smaller Neutral conductors. Unfortunately, emissions of harmonics (multiples of 3) add constructively in Neutral conductors and can reach 1.7 times the phase current in some installations. Overheating of conductors is aggravated by the skin effect, which tends to concentrate higher frequency currents towards the outside of the conductor, so that they experience greater resistance and create more heating effect. A further result of harmonic currents, especially when they leak into the earth network, is increased magnetic interference with sensitive systems operating in the audio band such as induction loop installations.
The non-sinusoidal current drawn from the supply causes distortion of the supply voltage, since the inductance of the supply increases the source impedance as the harmonic order rises. This waveform distortion can cause serious effects in direct-on-line induction motors, ranging from a minor increase in internal temperature through excessive noise and vibration to actual damage. Electronic power supplies may fail to regulate adequately; increased earth leakage current through EMI filter capacitors due to their lower reactance at the harmonic frequencies can also be expected.
System resonance effects at the harmonic frequencies can create areas of the power distribution network where the voltage is more heavily distorted than elsewhere, and/or has significant over- or under-voltage. Also, some areas of the network can suffer from much higher levels of current than elsewhere.
EMC testing – Commercial sector
Harmonics – Measurement equipment
ZM
E.U.T
GZs
Zs
ZM
POWER SUPPLY SOURCE
M
U
MEASUREMENT EQUIPMENT
ANALYZER
EMC testing – Commercial sector
Harmonics – Class A limit
• Balanced three-phase equipment
• Household appliances, excluding equipment identified by Class D
• Tools excluding portable tools
• Dimmers for incandescent lamps
• Audio equipment
• Everything else that is not classified as B, C or D
EMC testing – Commercial sector
Harmonics – Class B limit
Multiplied by a factor of 1,5
Portable tools
Arc welding equipment which is not professional equipment
EMC testing – Commercial sector
Harmonics – Class C limit
• Lighting equipment
EMC testing – Commercial sector
Harmonics – Class D limit
Equipment must have power level 75W up to and not exceeding 600W :
• Personal computers and personal computer monitors
• Television receivers
EMC testing – Commercial sector
Harmonics – Limits
EMC testing – Commercial sector
Harmonics – Results
EMC testing – Commercial sector
Flicker – Introduction Flicker is the impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or
spectral distribution fluctuates with time
Voltage fluctuations are caused by loads on the power distribution system which are located near lighting equipment (within the same building or powered by the same distribution transformer) and have changing power or current levels. The normal power distribution system has a source impedance high enough that appliances, heating equipment, cooking equipment, power tools and even office equipment can cause easily perceptible changes in lighting levels. If the load changes are of sufficient amplitude and frequency, they will disturb personnel working nearby
Varying current loads on a power supply network can result in voltage fluctuations at common points of connection, due to the series impedance of the network. These voltage fluctuations, if of sufficient amplitude, can cause flicker in luminaires connected to the same supply. This is a very old interference problem that dates from the very first public electricity supplies
EMC testing – Commercial sector
Flicker – Limits for short-term flicker indicator: Pst
Plt ≤ 0,65 is the flicker severity evaluated over a long period of time (2 hours)
Flicker – Limits for long-term flicker indicator: Plt
The flicker severity evaluated over a short period of time (10 minutes)
Pst ≤ 1 is the conventional threshold of irritability ad depends of the relative voltage change d (U/ Un) and therepetition rate of the changes
EMC testing – Commercial sector
Flicker – Other limits
The relative steady-state voltage change, dc, shall not exceed 3%.
The maximum relative voltage change, dmax, shall not exceed 4%.
The value of d(t) during a voltage change shall not exceed 3% for more than 200ms
If voltage changes are caused by manual switching or occur less frequently than once per hour, the Pst and Pltrequirements are not applied. The dc, dmax and d(t) limits are multiplied by 1.33
EMC testing – Commercial sector
Flicker – Measurement equipment
ZM
E.U.T
GZs
Zs
ZM
POWER SUPPLY SOURCE
M
U
MEASUREMENT EQUIPMENT
ANALYZER
EMC testing – Commercial sector
Electrostatic Discharges – Introduction
• Two materials with different dielectric constants can produce rubbing charge exchange between them, such that remaining charged. When one comes in contact with a material with low resistance to ground, is discharged through it until both potentials are equal.
• A person is charged due to charge exchange between the sole of his shoes and the ground by walking or friction on clothing. When this person touches an electronic equipment, a discharge may be flowing through the equipment to ground, being able to cause serious damage to the internal circuitry
• The test relates to the immunity requirements and test methods for electrical and electronic equipmentsubjected to static electricity discharges, from operatorss directly, and to adjacent objects
EMC testing – Commercial sector
Electrostatic Discharges – Current waveform
Defined current waveform
EMC testing – Commercial sector
Electrostatic Discharges – Parameters of the waveform
Level Voltage(KV)
Peakcurrent (A)
Risetime (ns)
Currentat 30ns (A)
Currentat 60ns (A)
1234
2468
7.515
22,530
0,7 – 10,7 – 10,7 – 10,7 - 1
48
1216
2468
EMC testing – Commercial sector
Electrostatic Discharges – Real current waveform
Current at 4 kV Current measured at 4 kV
EMC testing – Commercial sector
Electrostatic Discharges – Test levels
LevelVoltage Test
kV
1 2
2 4
3 6
4 8
x special
LevelVoltage test
kV
1 22 4
3 8
4 15
x special
EMC testing – Commercial sector
Electrostatic Discharges – Test set-up
1. Direct discharges
• Contact discharges: the static electricity discharges shall be applied only ton those points and surfaces of the EUT which are accessible to persons during normal use.
• Air discharges: Contacts with a non-conductive (for example plastic) surface and which are accessible shall be tested by the air discharge test only.
2. Indirect discharges
• Discharges to objects placed or installed near the EUT shall be simulated by applying the discharges of the ESD generator to a coupling plane, in the contact discharge mode.
EMC testing – Commercial sector
Electrostatic Discharges – Test set-up for table top equipment
EMC testing – Commercial sector
Electrostatic Discharges – Test set-up for ungrounded table top equipment
EMC testing – Commercial sector
Electrostatic Discharges – Test set-up for floor standing equipment
EMC testing – Commercial sector
Electrostatic Discharges – Test set-up for ungrounded floor standing equipment
EMC testing – Commercial sector
Radiated immunity – Introduction
• The electromagnetic radiation is frequently generated by such sources as the small hand-held radio transceivers that are used by operating, maintenance and security personnel, fixed-station radio and television transmitters, vehicle radio transmitters, and various industrial electromagnetic sources.
• In recent years there has been a significant increase in the use of radio telephones and other radio transmitters operating at frequencies between 0,8 GHz and 3 GHz. Many of these services use modulation techniques with a non-constant envelope
• In addition to electromagnetic energy deliberately generated, there is also spurious radiation caused by devices such as welders, thyristors, fluorescent lights, switches operating inductive loads, etc.
• The object of this test is to establish a common reference for evaluating the performance of electrical and electronic equipment when subjected to radio-frequency electromagnetic fields.
• Radiated electromagnetic field: E, H, continuous, modulated, pulsed
EMC testing – Commercial sector
Radiated immunity – Waveform
the test signal is 80 % amplitude modulated with a 1 kHz sinewave to simulate actual threats
EMC testing – Commercial sector
Radiated immunity – Test levels
Frequency range: 80 MHz to 1000 MHz
Level Test field strength (V/m)
1 1
2 3
3 10
x special
• Levels defined for unmodulated signal
• X is an open test level. This level may be given in the product specification
EMC testing – Commercial sector
Radiated immunity – Test levels
Frequency range: 800 MHz to 960 MHz and 1,4 GHz to 2,0 GHz.
• Levels defined for unmodulated signal
• X is an open test level. This level may be given in the product specification
Level Test level fieldstrength(V/m)
1 12 33 104 30x special
EMC testing – Commercial sector
Radiated immunity – Calibration
EMC testing – Commercial sector
Radiated immunity – General test set-up
Semianechoic chamber
EMC testing – Commercial sector
Radiated immunity – Test set-up for table top equipment
EMC testing – Commercial sector
Radiated immunity – Test set up for floor standing equipment
EMC testing – Commercial sector
Radiated immunity – Test example
EMC testing – Commercial sector
Power frequency magnetic immunity test – Introduction
• The power frequency magnetic field is generated by power frequency current in conductors or, more seldom from other devices (e.g. leakage of transformers) in the proximity of equipment.
• As for the influence of nearby conductors, one should differentiate between:
• The current under normal operation conditions, which produces a steady magnetic field
• The current under fault conditions which can produce high magnetic fields but of short durations, until the protection devices operate (a few miliseconds for fuses, a few seconds for protection relays.
• The test with a steady magnetic field may apply to all types of equipment intended for public or industrial low voltage distribution networks, or for electrical plants.
• The test with a short duration magnetic field related to fault conditions, requires test levels different from the steady state conditions. The highest values apply mainly to equipment to be installed in exposes places of electrical plants.
• The object of this test is intended to demonstrate the immunity of equipment when subjected to power frequency magnetic fields related to specific location and installation conditions of the equipment (e.g proximity of the equipment to the disturbance source)
• The phenomenon can significantly affect equipment with Hall effect devices (CRT tubes, loudspeakers, etc)
EMC testing – Commercial sector
Power frequency magnetic immunity test – Test levels for continuouds fields
Level Magnetic field stregth (A/m)
1 1
2 3
3 10
4 30
5 100
X special
• X is an open test level. This level may be given in the product specification
EMC testing – Commercial sector
Power frequency magnetic immunity test – Test set up for short durations
1 s to 3 s
Level Magnetic field stregth (A/m)
1 N/A
2 N/A
3 N/A
4 300
5 1000
X special
• X is an open test level. This level as well the duration of the test may be given in the product specification
• N/A: Not applicable
EMC testing – Commercial sector
Power frequency magnetic immunity test – Test set up
Table top equipment
Floor standin equipment
EMC testing – Commercial sector
Power frequency magnetic immunity test – Test example for 300 A/m
A2
A1
V1 V2 V3 H1
TRFVariacAntenna MS 100
I1 I2
F Ant = 0.9mF Trf = 6 AV-1
F Ant = 0.9mF Trf = 6 AV-1
I Antenna = 300Am-1/0.9m = 270 A
U Primary = 270A / 6.AV-1 = 45 V
EMC testing – Commercial sector
Power frequency magnetic immunity test – Test example for 300 A/m
Personal Computerunder test
EMC testing – Commercial sector
EFT/Burst – Introduction
• The electrical fast transients and bursts are originated from switching transients as interruption of inductive loads, relay contact bounce, power units, compressors, etc.
• This type of physical phenomenon raises many problems on existing equipment, whether analog or digital. These bursts may be able to charge the parasitic capacitances of the circuits or interfere in microprocessors. In the short term it can lead to the destruction of the components and in a longer term accelerate the aging of the components.
• The object of this test is intended to demonstrate the immunity of electrical and electronic equipment when subjected to electrical fast transients and bursts
EFT/Burst – Waveshape of a single pulse into a 50 Ω load
EMC testing – Commercial sector
EFT/Bursts – General graph
EMC testing – Commercial sector
EFT/Bursts –Test levels
Open circuit output voltage and repetition rate of the impulses
Power port, PE I/O signal, data and
control ports
Level VoltagekV
FrequencykHz
VoltagekV
FrequencykHz
1 0.5 5 or 100 0.25 5 or 100
2 1 5 or 100 0.5 5 or 100
3 2 5 or 100 1 5 or 100
4 4 5 or 100 2 5 or 100
X” special special special special
EMC testing – Commercial sector
EFT/Bursts – General test set up
EMC testing – Commercial sector
EFT/Bursts – Test set up for AC/DC power supply terminals and PE
EMC testing – Commercial sector
EFT/Bursts – Test set up for I/O signal, data and control ports
EMC testing – Commercial sector
Surges – Introduction
• Surges are caused by overvoltage from switching and lightning transients .
1. Switching transients can be separated into transients associated with:
• Major power system switching disturbance (capacitor bank switching)
• Minor switching activity near the instrumentation or load changes in the power distribution system
• Resonating circuits associated with switchin devices
• Shorts circuits and arcing faults ton the earthinh system of the installation
EMC testing – Commercial sector
Surges – Introduction
2. Lightning transients:
• A direct lightning stroke to an external circuit (outdoor) injecting high currents producing voltage by either flowing through earth resistance or flowing through the impedance of the external circuits
• Lightning earth current flow resulting from nearby direct to earth discharges coupling into the common earth paths of the earthing system of the installation
• An indirect lightning stroke that induces voltages/currents on the conductors outside and/or inside a building
EMC testing – Commercial sector
Surges – Waveform of open circuit voltage (1,2/50 µs)
EMC testing – Commercial sector
Surges – Waveform of short-circuit current (8/20 µs)
EMC testing – Commercial sector
Surges – Waveform of open circuit voltage (10/700 µs)
EMC testing – Commercial sector
Surges – Waveform of short-circuit current (5/320 µs)
EMC testing – Commercial sector
Surges – Test set up AC/DC lines: Line to line
CAPACITIVE COUPLING
EMC testing – Commercial sector
Surges – Test set up AC/DC lines: Line to ground
CAPACITIVE COUPLING
EMC testing – Commercial sector
Surges – Test set up : unshielded unsymmetrically interconnections lines
CAPACITIVE COUPLING
EMC testing – Commercial sector
Surges – Test set up : unshielded unsymmetrically interconnections lines
COUPLING VIA ARRESTORS
EMC testing – Commercial sector
Surges – Test set up: unshielded symmetrically interconnections/telecommlines
COUPLING VIA ARRESTORS
Calculation of Rm2
For n= 4
a) Using generator 1.2/50 s
Rm2= 4 x 40 = 160 , max. 250
a) Using generator 10/700 s
Rm2= 4 x 25 = 100 , max. 250
EMC testing – Commercial sector
Surges – Test set up: unshielded symmetrically interconnections/telecomm. Lines (1,2/50 µs). High speed telecomm. lines
RC = RD = 80
RA y RB
CAPACITIVE COUPLING
EMC testing – Commercial sector
Surges – Test set up: shielded lines at both ends
COUPLING BY CONDUCTION
EMC testing – Commercial sector
Surges – Test set up: unshielded lines and shielded lines earthed only at one end
COUPLING BY CONDUCTION
EMC testing – Commercial sector
Conducted immunity – Introduction
• The conducted RF electromagnetic fields are generated by all type of transmitters in frequency band from 9 kHz to 80 MHz: the small hand-held radio transceivers that are used by operating, maintenance and security personnel, fixed-station radio, vehicle radio transmitters, and various industrial electromagnetic sources.
• The source disturbance covered by this procedure is basically an electromagnetic field coming from intended RF transmitters that may act in the whole length of cables connected to an installed equipment.
• The dimensions of the disturbed equipment, mostly a sub-part of a larger system, are assumed to be small compared with the wavelengths involved.
• The in-going and out-going leads: e.g. mains, communication lines, interface cables behave as passive receiving antenna networks because they can be several wavelengths long
• Equipment not having at least one conducting cable (such as mains supply, signal line or earth connection) which can couple the equipment to the disturbing RF fields is excluded
EMC testing – Commercial sector
Conducted immunity – Waveform
the test signal is 80 % amplitude modulated with a 1 kHz sinewave to simulate actual threats
EMC testing – Commercial sector
Conducted immunity – Test levels
EMC testing – Commercial sector
Conducted immunity – Calibration using CDNs
The test generator shall be connected to the RF input port of the coupling device. The EUT port of the couplingdevice shall be connected in common mode through the 150 Ω to 50 Ω adapter to a measuring equipment having a 50 Ω input impedance. The AE port of the CDN shall be loaded in common mode with a 150 Ω to 50 Ω adapter, terminated with 50 Ω .
EMC testing – Commercial sector
Conducted immunity – Calibration using 50 Ω jig
When the level setting for current clamps is carried out in a 50 Ω test environment, the voltage, Umr appearingacross the 50 Ω load shall be 6 dB less than the test level required. In this case, the measured voltages or resultingcurrents in the 50 Ω test jig are equal to
EMC testing – Commercial sector
Conducted immunity – Test set up using CDN
EMC testing – Commercial sector
Conducted immunity – Test set up using Injection clamp
EMC testing – Commercial sector
Conducted immunity – Test set up for shielded cable
EMC testing – Commercial sector
Conducted immunity – Test set up for single unit EUT
EMC testing – Commercial sector
Conducted immunity – Test set up for single unit EUT using Injection clamp
EMC testing – Commercial sector
Conducted immunity – Test set up for multi-unit EUT
EMC testing – Commercial sector
Voltage dips, short interruptions and voltage variations - Introduction
• The object of this tests is to establish a common reference for evaluating the immunity of electrical and electronicequipment when subjected to voltage dips, short interruptions and voltage variations.
• The Electrical and electronic equipment may be affected by voltage dips, short interruptions or voltage variations of power supply
• Voltage dips and short interruptions are caused by faults in the network, primarily short circuits, in installations or by sudden large changes of load. In certain cases, two or more consecutive dips or interruptions may occur
• Voltage variations are caused by continuously varying loads connected to the network.
• These phenomena are random in nature and can be minimally characterized in terms of the deviation from the rated voltage and duration.
• Voltage dip: a sudden reduction of the voltage at a particular point of an electricity supply system below a specified dip threshold followed by its recovery after a brief interval
• Short interruption: a sudden reduction of the voltage on all phases at a particular point of an electric supply system below a specified interruption threshold followed by its restoration after a brief interval. Short interruptions are typically associated with switchgear operations related to the occurrence and termination of short circuits on the system or on installations connected to it
EMC testing – Commercial sector
Voltage dips, short interruptions and voltage variations - Waveforms
Voltage dip – 70 % voltage dip sine wave graph
EMC testing – Commercial sector
Voltage dips, short interruptions and voltage variations - Waveforms
Voltage dip – 40 % voltage dip r.m.s. graph
EMC testing – Commercial sector
Voltage dips, short interruptions and voltage variations - Waveforms
Short interruption
EMC testing – Commercial sector
Voltage variation
Voltage dips, short interruptions and voltage variations - Waveforms
EMC testing – Commercial sector
Voltage dips – Preferred test level and durations
EMC testing – Commercial sector
Short interruptions - Preferred test level and durations
EMC testing – Commercial sector
Voltage variations - Preferred test level and durations
EMC testing – Commercial sector
Voltage dips, short interruptions and voltage variations – Test set up usingvariable transformers and switching
EMC testing – Commercial sector
Voltage dips, short interruptions and voltage variations – Test set up usingpower amplifier
EMC testing – Commercial sector
Voltage dips, short interruptions and voltage variations - Test set up usingtapped transformers and switches
EMC testing – Commercial sector
Quenstions
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