Yngve Hamnerius

12. Elektriciteten i vardagen

Yngve Hamnerius professor Chalmers University of Technology

1

50 Hz electric current perception values (Iw) for different perception

probabilities (p)

2

Cumulative probability that an individual with a 60 Hz current passing to her hand will not be

able to let go

Child 5 – 10 mA

3

Elektricitet i vardagen

Electric fields

•  E = U/d (V/m)

5

6

Magnetic fields

H =I

2π ⋅ r

B = µ ⋅H

A current, I, goes through a strait infinite conductor will create a magnetic field strength, H (A/m) at the distance, r.

The magnetic flux density B (T) is,

Field line

Strait conductor

7

MAGNETISKA FÄLT

8

The current density for the man |J

| [m

A/m²](

rms v

alue

)

|J| [

mA

/m²](

rms v

alue

)

1cm2 averaged results: unaveraged results:

Magnetic and electric stimulation at depression and neurological decease TMS

(transcranial magnetic stimulation) or ECT (electroconvulsive therapy)

TMS ECT

Currents

TMS ECT

J [A

/m2] J

[A/m

2]

Elektricitet i vardagen

tIe ⋅

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Elektricitet i vardagen

AIVV

kR

e

e

2.02301

≈

=

Ω≈

Elektricitet i vardagen

Elektricitet i vardagen Transformator

E1e/E2e = N1/N2

Elektricitet i vardagen

Elektricitet i vardagen

Elektricitet i vardagen

Measured magnetic fields Green < 0.2 µT, yellow 0.2-1.0 µT, red > 1.0 µT

20

Four conductor system can give rise to stray currents

21

Magnetic fields registered in a flat

22

Circulation pump for heating

23

Five conductor system prevents from stray currents

24

Booster transformer core

25

Booster transformer

transform

er

load

Metal cabinet

Metal pipe

fuses

26

Magnetic field before (blue) and after (red) installation of a booster transformer

27

Average magnetic fields

Childhood leukemia and Magnetic fields Ahlbom et al.,

British Journal of Cancer (83, p.692-698, 2000).

0,1 1 10

>= 0.4 µT

0.2 - 0.4 µT

0.1 - 0.2 µT

< 0.1 µT

RR

2.00 (1.27-3.13)

IARC Evaluation of Carcinogenic Risks to Humans

•  IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Static and Extremely Low Frequency Electric and Magnetic Fields (Vol. 80) 2002

IARC ���International Agency for Research on Cancer

Group 1 “Are carcinogenic to humans” Arsenic, Asbestos, Benzene, Beryllium, Cadmium, Ethylene oxide

Group 2A “Are probably carcinogenic” Ethylene dibromide, Formaldehyde, Vinyl bromide

Group 2B “Are possibly carcinogenic” Acrylamide, Chloroform, Diesel fuel, Lead, ELF magnetic fields, Welding fumes

IARC ���International Agency for Research on Cancer

Group 3 “Are not classifiable as to their carcinogenicity”Group 4 “Are probably not carcinogenic”

•  Utvärderingen utfördes vid möte på IARC i Lyon den 9-13 mars 2015.

•  Yngve Hamnerius var en av de röstberättigade medlemmarna i utvärderingskommittén

•  Den nya utvärderingen ledde till samma klassning 2B “möjlig carcinogen” som tidigare

Ny utvärdering i projektet ARIMMORA på IARC

Elektricitet i vardagen

Elektricitet i vardagen