EMC TESTING - IAS - Alter Technology · EMC testing - COMMERCIAL sector ... National: UNE-EN, BS, NF, VDE, ANSI, VCCI…. Basic Standards ... IEC 6100-4-3 EN 61000-4-3 UNE-EN 61000-4-3

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


Radiated disturbances – Measurement site a) Test site b) alternative test site


Radiated disturbances – Measurement site Semianechoic chamber


Radiated disturbances – Measurement site Semianechoic chamber calibartion: NSA measurement

Typical antenna positions for alternate site NSA measurements

Vertical polarization Horizontal polarization


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


Radiated disturbances – Measuring equipment

Antenna bilog Log-per antenna radiation pattern

Antennas

Linear polarized antennas: dipole, biconnical, log-per, bilog and horns

Biconnical antenna


Emission interferences – Measuring equipment

Receivers or spectrum analyzers in accordance with EN 55016-1-1

Receivers Spectrum analyzer

Preselector + QP adapter



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



AMN, LISN and ISN impedance


Emission interferences – Type of measurements

Peak Average Quasi-peak

1

2

t2 t1

A/3

A


Emission interferences – Limits


Radiated disturbances – Limit class A

Radiated disturbances – Limit class B


Radiated disturbances – Limit class A

Radiated disturbances – Limit class B


Radiated disturbances – General test set-up

EUT

Antenna

3 or 10 m


Radiated disturbances – General test set-up

EUT

Turntable

Receiver

1 to 4 m


Radiated disturbances – Test arrangement for tabletop equipment (top view)

EUT


Radiated disturbances – Test arrangement for tabletop equipment

EUT


Radiated disturbances – Test arrangement for floor-standing equipment

EUT


Radiated disturbances – Test arrangement for combinations of equipment

EUT


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


Radiated disturbances – Results

EUT


Conducted disturbances – Mains terminals (AC or DC). Limit class A

EUT

Conducted disturbances – Mains terminals (AC or DC). Limit class B


Conducted disturbances – Telecommunication ports. Limit class A

EUT

Conducted disturbances – Telecommunication ports. Limit class B


Conducted disturbances – Test arrangement for tabletop equipment (top view)

EUT


Conducted disturbances – Test arrangement for tabletop equipment. Alternative 1a


Conducted disturbances – Test arrangement for tabletop equipment. Alternative 1b


Conducted disturbances – Test arrangement for tabletop equipment. Alternative 2


Conducted disturbances – Test arrangement for floor-standing equipment


Conducted disturbances – Test arrangement for combinations of equipment


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


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



As previous slide or using the following set-up


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



Using a combination of current probe and capacitive voltage probe


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



Using no shield connection to ground and no ISN


Conducted disturbances on mains terminals - Results


Conducted disturbances on telecommunication ports - Results


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


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.


Harmonics – Measurement equipment

ZM

E.U.T

GZs

Zs

ZM

POWER SUPPLY SOURCE

M

U

MEASUREMENT EQUIPMENT

ANALYZER


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


Harmonics – Class B limit

Multiplied by a factor of 1,5

Portable tools

Arc welding equipment which is not professional equipment


Harmonics – Class C limit

• Lighting equipment


Harmonics – Class D limit

Equipment must have power level 75W up to and not exceeding 600W :

• Personal computers and personal computer monitors

• Television receivers


Harmonics – Limits


Harmonics – Results


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


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


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


Flicker – Measurement equipment

ZM

E.U.T

GZs

Zs

ZM

POWER SUPPLY SOURCE

M

U

MEASUREMENT EQUIPMENT

ANALYZER


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


Electrostatic Discharges – Current waveform

Defined current waveform


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


Electrostatic Discharges – Real current waveform

Current at 4 kV Current measured at 4 kV


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


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.


Electrostatic Discharges – Test set-up for table top equipment


Electrostatic Discharges – Test set-up for ungrounded table top equipment


Electrostatic Discharges – Test set-up for floor standing equipment


Electrostatic Discharges – Test set-up for ungrounded floor standing equipment


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


Radiated immunity – Waveform

the test signal is 80 % amplitude modulated with a 1 kHz sinewave to simulate actual threats


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


Radiated immunity – Test levels

Frequency range: 800 MHz to 960 MHz and 1,4 GHz to 2,0 GHz.

• Levels defined for unmodulated signal


Level Test level fieldstrength(V/m)

1 12 33 104 30x special


Radiated immunity – Calibration


Radiated immunity – General test set-up

Semianechoic chamber


Radiated immunity – Test set-up for table top equipment


Radiated immunity – Test set up for floor standing equipment


Radiated immunity – Test example


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)


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



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


Power frequency magnetic immunity test – Test set up

Table top equipment

Floor standin equipment


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


Power frequency magnetic immunity test – Test example for 300 A/m

Personal Computerunder test


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


EFT/Bursts – General graph


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


EFT/Bursts – General test set up


EFT/Bursts – Test set up for AC/DC power supply terminals and PE


EFT/Bursts – Test set up for I/O signal, data and control ports


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


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


Surges – Waveform of open circuit voltage (1,2/50 µs)


Surges – Waveform of short-circuit current (8/20 µs)


Surges – Waveform of open circuit voltage (10/700 µs)


Surges – Waveform of short-circuit current (5/320 µs)


Surges – Test set up AC/DC lines: Line to line

CAPACITIVE COUPLING


Surges – Test set up AC/DC lines: Line to ground

CAPACITIVE COUPLING


Surges – Test set up : unshielded unsymmetrically interconnections lines

CAPACITIVE COUPLING


Surges – Test set up : unshielded unsymmetrically interconnections lines

COUPLING VIA ARRESTORS


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


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


Surges – Test set up: shielded lines at both ends

COUPLING BY CONDUCTION


Surges – Test set up: unshielded lines and shielded lines earthed only at one end

COUPLING BY CONDUCTION


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


Conducted immunity – Waveform

the test signal is 80 % amplitude modulated with a 1 kHz sinewave to simulate actual threats


Conducted immunity – Test levels


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 .


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


Conducted immunity – Test set up using CDN


Conducted immunity – Test set up using Injection clamp


Conducted immunity – Test set up for shielded cable


Conducted immunity – Test set up for single unit EUT


Conducted immunity – Test set up for single unit EUT using Injection clamp


Conducted immunity – Test set up for multi-unit EUT


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


Voltage dips, short interruptions and voltage variations - Waveforms

Voltage dip – 70 % voltage dip sine wave graph



Voltage dip – 40 % voltage dip r.m.s. graph



Short interruption


Voltage variation



Voltage dips – Preferred test level and durations


Short interruptions - Preferred test level and durations


Voltage variations - Preferred test level and durations


Voltage dips, short interruptions and voltage variations – Test set up usingvariable transformers and switching


Voltage dips, short interruptions and voltage variations – Test set up usingpower amplifier


Voltage dips, short interruptions and voltage variations - Test set up usingtapped transformers and switches


Quenstions

THANK YOU FOR YOUR ATTENDANCE

Documents

EMC TESTING - IAS - Alter Technology · EMC testing - COMMERCIAL sector ... National: UNE-EN, BS, NF, VDE, ANSI, VCCI…. Basic Standards ... IEC 6100-4-3 EN 61000-4-3 UNE-EN 61000-4-3