http://sah9.blogspot.com

http://sah9.blogspot.com

http://sah9.blogspot.com
Gujarat Technological
University
Ahmadabad India

Effects
of
Electromagnetic Fields
http://sah9.blogspot.com

Contains :
Introduction
Concept of Electromagnetic Interference and Compatibility
EMI sources:
Effects of EMI
Methods To Eliminate EMI
EMC Standards
Advantages of EMC standards.
Biological effects of EMI
Conclusion.
Reference
http://sah9.blogspot.com

Introduction :
•An electromagnetic field is a physical field produced by electrically
charged objects.
• It affects the behavior of charged objects in the vicinity of the field
•The field can be viewed as the combination of an electric field and a
magnetic field. http://sah9.blogspot.com

http://sah9.blogspot.com

Concept of Electromagnetic Interference and
Compatibility :
• Electromagnetic interference (EMI), also called radio-frequency
interference or RFI when in radio frequency,
• Is disturbance that affects an electrical circuit due to either
electromagnetic induction or electromagnetic radiation emitted from an
external source.
•Electromagnetic compatibility (EMC) is the branch of electrical
sciences which studies the unintentional generation, propagation
and reception of electromagnetic energy with reference to the
unwanted effects (electromagnetic interference, or EMI) that such
energy may induce.
http://sah9.blogspot.com

EMI sources:
Communication Devices
Heavy Machinery
HVAC Equipment
MRI Machines
Radio Signals
The Sun
Other Sources like Door ball, transformer, toaster
ovens, Ultrasonic pest control device,
Wireless device like Bluetooth, cordless telephone,
video senders and microwave ovens.
™Air craft navigation and military equipments
http://sah9.blogspot.com

http://sah9.blogspot.com

Effects of EMI
i. Extremely low frequency RF:
ii. Shortwave frequency RF:
iii. Microwaves:
iv. Millimeter waves:
v. Infrareds:
vi. Visible light:
vii.Ultraviolet:
viii.Radio frequency fields:
http://sah9.blogspot.com

Above fig. shown the different between with EMI And with EMI
Cancellation. http://sah9.blogspot.com

Methods To Eliminate EMI
• Characterizing the threat:
Characterization of the problem requires understanding of:
 The interference source and signal.
 The coupling path to the victim.
 The nature of the victim both electrically and in terms of the significance of
malfunction.
• Laws and regulators:
1. Laws:
Compliance with national or international standards is usually required by laws
passed by individual nations. Different nations can require compliance with
different standards.
http://sah9.blogspot.com

2. Regulatory and standards bodies:
Several international organizations work to promote international co-operation
on standardization (harmonization), including publishing various EMC standards.
Where possible, a standard developed by one organization may be adopted with
little or no change by others. This helps for example to harmonize national
standards across Europe. Standards organizations include:
• EMC design:
1. Grounding and shielding:
Grounding or earthing
Shielded cables
Shielded housings
2. Other general measures:
Decoupling or filtering
Transmission line
Avoidance of Antenna Structures
3. Emissions suppression:
http://sah9.blogspot.com

EMC Standards
These standards attempt to standardize product EMC performance, in respect
to radio interference for electrical equipment.
The following list of EMC standards:
1 CISPR standards
2 IEC standards
3 ISO standards
4 European standards concerning unwanted electrical
emissions
5 European standards concerning immunity to electrical
emissions
6 American standards
http://sah9.blogspot.com

 DOD - Department of Defence (USA) -- Immunity and
Emission MIL standards.
 IEC - International Electro technical Commission (EU)
Immunity standards.
 ™CISPR - International Special Committee on Radio
Interference Operating under IEC. -- Emission Standards. ™
 FCC - Federal Communication Commission ( EU ) ---
Emission standards. ™
 BSI - British Standard Institution ( UK ) -- Emission
standards. ™
 VDE - Verb and Deutscher Electrotechniker (Germany) -
Emission standards.
http://sah9.blogspot.com

Important Immunity Standards ™
 IEC 61000-4-2 : Electrostatic Discharge immunity test.
 ™IEC 61000-4-3 : Radiated radio frequency EM field immunity test.
 ™IEC 61000-4-4 : Electrical fast transient / Burst immunity test.
 ™IEC 61000-4-5 : Surge immunity test. ™
 IEC 61000-4-6 : Conducted radio frequency EM field immunity test.
 ™IEC 61000-4-8 : Power frequency magnetic field immunity test.
 ™IEC 61000-4-11 : Voltage Dips, short interruptions and voltage
variations immunity test.
http://sah9.blogspot.com

Important Emission Standards ™
 CISPR 11 : Industrial, Scientific and Medical equipments.
 ™CISPR 12 : Automobiles ™CISPR 13 : Audio visual and similar
apparatus.
 ™CISPR 14 : Household and similar electrical appliances.
 ™CISPR 15 : Electrical Lighting and similar equipments.
 ™CISPR 22 : Information Technology equipments.
 ™FCC Part 15 : Radio Frequency Devices.
 ™FCC Part 18 : Industrial, Scientific and Medical equipments.
 ™IEC 61000-3-2 : Limits of harmonic current emission (< 16A per
phase)
http://sah9.blogspot.com

Advantages of EMC standards.
The advantages are:
Compatibility, reliability and maintainability are increased.
Design safety margin is provided.
The equipment operates in EMI scenario satisfactorily.
Product life and profit are increased.
EM spectrum protection. ™
Adequate power quality. ™
Compatibility between collocated electrical and electronic
systems for trouble free operation .
http://sah9.blogspot.com

Biological effects of EMI
Genetic effect
Cancer
Behavioral changes
Nervous system
Blood brain barrier
Hormonal disturbance
Metabolically effect
http://sah9.blogspot.com

Conclusion
After studying electromagnetic interference /
compatibility. We have conclude about the concept, sources ,
standard Electromagnetism interference / compatibility.
Interference mitigation and hence electromagnetic
compatibility is achieved by addressing both emission and
susceptibility issues Interference mitigation and hence
electromagnetic compatibility is achieved by addressing
both emission and susceptibility issues, i.e., quieting the
sources of interference and hardening the potential victims.
The coupling path between source and victim may also be
separately addressed to increase its attenuation.
http://sah9.blogspot.com

• Reference:
www.nasa.gov/centers/johnson
http://en.wikipedia.org
http://web.mit.edu/viz/EM/visualizations/guidedtour/Tour.ht
m#_Toc27302365
http://phys23p.sl.psu.edu/phys_anim/EM/indexer_EM.html
Field theory ,published by tech max ,author by sandeep
wali
www.slideshow.com
http://www.sameercal.org/docs/emi-emc-pdf.pdf
http://sah9.blogspot.com

follow me :
http://sah9.blogspot.com
WWW.Facebook.com/Sah92786
https://www.linkedin.com/in/arshad-hussain-8b0a2613b
http://sah9.blogspot.com

http://sah9.blogspot.com