bizarre emi incidents

8/6/2019 Bizarre EMI Incidents

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1BIZARRE EMI INCIDENTS

Naval EMC CentreMumbaiWelcomes you to

Bizarre EMIIncidents

Lt Cdr A Saxena


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Patients arm amputated blood

circulation monitoring system failed dueto plastic welding machine.

Security breached data loaded on a PC

by wireless keyboard in another room 150metres away.

Ships data-log failure automated

system resets every night at 2300 hrs.


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Bizarre yet True !!

Welcome t o the

wor ld o fEMI


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IntroductionHow Interference Takes PlaceSources of EM EnergyCoupling Paths

Bizarre Incidents

Aviation

MedicalGeneral Engineering

Naval

Way - Points


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All electronic equipmentemit EM energy.

When coupled to otherdevices, this energy candegrade their

performance - called EMI.

ELECTROMAGNETICINTERFERENCE


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All three elementsmust exist together

for EMI to occur

Source Victim

Coupling Path

EMI

Conduction Radiation

ELEMENTS OF EMI


7/617BIZARRE EMI INCIDENTS

Natural: Due to Natural Phenomena.Solar/Cosmic/Thunderstorm/Lightning

Incidental: From Sources, Not Intended to

Radiate.Functional: From Sources, Intended to

Radiate.

Secondary Sources: Interaction of EMEnergy and other metallic structures likeframes, hull etc.

SOURCES OF EMI



Designed to radiate energy during normaloperation

OWN JAMMERS

MISSILESEEKERHEADS

COMMUNICATIONLINKS

(SHIPS / AIRCRAFTS/ UAV / MISSILES)

RADARS

FUNCTIONAL SOURCES



Not designed to radiate EM energy

DC MOTORS

ELECTRICALCONTROLLER

S

ENGINES&

IGNITERS

COMPUTERS POWERLINES

WELDINGMACHINES

FLUORESCENT LIGHTING

INCIDENTAL SOURCES



ConductedPower lines

Signal lines

Radiated

Directly on systemOn to cables connected to the system

COUPLING PATHS



CommonPowerSupply

Source of Transient/ EMI

Victim

ConductedEmission

POWER LINE CONDUCTED

EMI


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CommonUtility

SignalSource 1

SignalSource 2

Power Supply

Power Supply

SIGNAL LINE CONDUCTED EMI


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Weather Deck

Tx Rx

14

ANTENNA TO ANTENNACOUPLING


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Upper-deck Cable

15

Victim

TopsideEquipment

Below Deck

Above Deck

Tx

ANTENNA TO CABLE COUPLING


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Victim Victim

16

Equipment connected toInterference

SourceInterference

Source

CABLE TO CABLE COUPLING


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Could be intriguing

Might be amusing

Certainly be educative

BIZARRE EMI INCIDENTS


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Kennedy Space Centre1990sNASA reference publication1374Erroneous signal detectedduring on-pad checkoutPotential threat of launch

failure

Incident # 1 Saturn

launch vehicle


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Signal not traced toany known source. Inter-modulationproducts formed at non-

linear junction onimproperly bondedhinged cable traycovers and chain

handrails on gantryframe. Spurious signalscapable of engine cutoff command and arm &

Analysis

Chain handrails ongantry frame


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20BIZARRE EMI INCIDENTS 20

F1

F2

F2

F1

F1

F2

F1

F2

F2

F1F1

F2

The badOne !

Inter Modulation Interference


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F1

F2

F2

F1F1

F2

F1

F2

F1

F2

F1

F2

F1

F2

Non-linear

Junction



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Non-linear Junction

22

F3 F3 = mF1 +nF2



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ITEM 2002, pages 54-

60. Airplane navigation &communication eqptmalfunction when

flying through rain.

Incident # 2 Rain rain goaway


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Analysis Static charge on aircraft skin exceeds 100kV

during rain. High voltage caused arcing between poorlybonded surfaces.

Resultant broadband noise interferes with

on-board systems.

+ + + + + + + + + + + + ++ +

+ + + + +

- - - - - - - - - - - - - - - - - - - - - - - - - - -- -

+ +

+ +

+ +

+ +

+

+ -

-

- -

- -

- - - -

- - - -

- - - Poorly

bonded

surface


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Gnd

V1

Gnd

Arc being formed due to non-conducting gap

Broadband Noise (BBN)


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Lightning appearedon Naval aircraft.

Pilot suffered fromblindness for 10-15secs.

Cockpit power failure.

In another flash, allpower restoredwithout any indicationof equipment

malfunction.

Incident # 3 Lightningcan and will strike


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Hobart, Tasmania Mid 90s New Scientist,

24th April 1999,page 100

Residents trappedin garages

Remote controlsfail

Incident # 4 Trapped inGarages


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USS Carl Vinsonentered harbour

Navigation radarat same frequencyas remotes

Malfunction due to

co-channelinterference

Analysis


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Co-channelinterference due

to improperallocation of frequencies.

Later on, coding

incorporated intoradio operatedcontrols toeliminate

interference.

Co-Channel Interference


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Incident # 5 Wheel Chair

MalfunctionEarly 2000IEEE International EMC

Symposium, Aug 2002A wheel chair suddenlydrove off a subway-platform.Handicapped personinjured critically.


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Chair activated due to digital telephone networkfield at 1.89 GHz.Chair tested for radiated susceptibility but onlytill 1 GHz.Manufacturer sentenced for putting unsafeproduct to market.

Analysis


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Sydney, AustraliaEarly 2000Graham Eckersall G4HFG/ W4HFG, 6th Jul 01Radio controlled garagedoors open and closerandomlySome refuse toopen/close at all

Incident # 6 Garage

Doors, yet again


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6 9 . 7 5 M H z

9 6 .9 M H z

Nova broadcasts - 96.9 MHzABC TV sound signal - 69.MHz

2 7 . 1 5 M H z

Analysis


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HMAS Huon & HMASAnzac

Early 2000 The Courier Mail, Feb

1st 2002 Near collision - HMAS

Huon loses controland veers across thebow of HMAS Anzac

Incident # 7 A CloseEncounter


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Analysis

Steering gear failureof Huan due to EMIfrom emitters onboard Anzac

Systems not tested toappropriate standards

Testing philosophyreviewed for all newlyinducted equipment


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EMI/EMC Testing

Testing as per Mil Std461 C/E mandatory forall equipment.

COTS equipmentprone to malfunctionin dense EMenvironment onboard.


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UK, 2002 www.roxtec.co.in Automatic logger on

passenger ferry resetswhile passing certainpoint on leavingharbour.

Always happened inevening, around 2300hrs.

Never occurred whilearrivin .

Incident # 8 Ship Data-Log Erased
http://www.roxtec.co.in/http://www.roxtec.co.in/


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A l i


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AutoData

Logger

HotPlates

SupplyBreaker

Analysis

Ferry auto-logger

Hot plates in

galley turned off daily at 2300 hrs. Transient in

common power

supply causedauto-logger toreset.

A l i


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CADNode

CopyingMachine

SupplyBreakerNetworked CAD

Failures coincidedwith operation of adrawing copyingmachine.

Switching

transients injectedonto the ring main.

Analysis


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Yankee Station,Pacific Ocean

10:52 AM July 29,1967

Un-commandedrelease of missilefrom own aircraftparked on flight deck.

134 men killed, 27aircraft lost. Total loss

72 million dollars.

Incident # 10 ForrestalDisaster

A l i


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Powerful fields at deck level from the shipsradar Incorrectly fitted shielded cable connector.Zuni rocket triggered.

Analysis


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Altincham, UK 1980s Stan Lomax of RTM

Group ltd, Mar 99 French make chart

recorder ran at double

speed on Saturdays

Incident # 11 Faster,

faster

A l i


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More TVs and radios inuse on Saturdays

Second harmonic

currents injected intothe mains Synchronous motors in

chart recorders

responds to 100 Hzdistortion Starts running twice as

fast

Analysis

N = 120 f /P

H i


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Harmonics

Harmonics aremultiples of theprimary frequency.

Can causeinterference wellbeyond the expectedband of operation.


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Netherly & Balbeggie,Scotland

Mid 1990s 7th International

Conference on Harmonicsand quality of Power (IEEE),Oct 1996

Payphones too noisy touse.

Rolling pictures on TV sets. Ringing on the supply to

fluorescent lighting circuits.

Incident # 12 No TV, notalk, only walk

A l i


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Two new oil pumpingstations installed.

33 KV power lines of induction drivespassing close to

residential areas. Higher orderharmonics (beyond100th) causing

interference.

Analysis


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Europe, 1990sCompliance Engineering

Magazines European editionSept/Oct 1994. Monitor/defibrillatorattached to heart patientshut down every timetechnicians used radiotransmitter for advice.

Patient dies.

Incident # 13 Medicaladvice causes death?

A l i


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Long range radio antenna fitted on

ambulance. Ambulance roof changed from metal tofiberglass

Significant reduction in EM shielding. Reduced shielding coupled with strongradiated power caused malfunction of equipment.

Analysis


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SHIELDING MODEL

Incident Energy

Reflected Energy

Shield

Absorptive Region

Penetrating Energy

I id # 14 I f


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New JerseyEarly 80s

Doug McKean, [email protected] infant deaths inIntensive Care SectionLate at night, the alarms onbabies monitors go off Annoyed nurses turns off alarm

Incident # 14 InfantMortality

Analysis


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Nearby TV transmitter allowed to increasedoutput wattage after midnight by FCC.Radiated noise coupled to un-shielded alarmcables.

Alarm

Nurse Stn

Cable

Analysis

Incident # 15 Stop that


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Incident # 15 Stop thatTrain

EuropeLate 90s

Jennifer Cortese,Melbourne, Dec 2000Certain type of locomotive passing by

radio station brakessuddenly. Oh comeon notagain!!!

Analysis


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Cables of temperaturesensor within tractionmotors not screened.Radio signals beingpicked up by sensorscausing the MCB to open.Modification veryexpensive as sensorswere mounted withinwindings of motors.

Analysis

Incident # 16 Cable TV


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Incident # 16 Cable TV,No TV

Set top box placed ontop of TV disruptspicture after 2-5minutes.Interference evenwhen no cablesconnected.All efforts bydesigners in vain.

A l i


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SETTOP BOXInterference due toMagnetic fields fromstereo speakers.Similar problemswith all metallicobjects.

Resolved byremoving Set-top boxfrom vicinity.

Analysis

I id t # 17 C k


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Incident # 17 Car park security

PortsmouthEaster 2001Anne Cameron, Alenia

Marconi Systems, 6th Jul01Cars parked insideshopping mall parking lotnot unlocking.Cars getting locked assoon as they are

unlocked.

I id t # 18 B th


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Incident # 18 BreathAnalysis

USARecentFrom an Ex-copFalse indications frombreath analyzer.People charged finedespite being innocent.

Anal sis


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EM radiations from video surveillancesystem interfere with car central locking andsecurity systems.Interference from the radio handsets causedmalfunctioning of breath analyzer

Analysis


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An Insight into the futurePossible article in Defence Review

Weekly, 2050

NATO Exercise Tech Savvy Forces

FailsGreat chaos as large portion of COTSequipment malfunctioned.

Attacking forces takeover, despite being on foot, armed only with vintage

equipment & communicating by shouting.


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