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Field Finder

Field Finder

© Enviromentor AB 1998 reg. 98.011/Eng

9

4

Measurement examples

4.1

Electric fields

Below is a suggestion as to how to measure an
electric field in a room within the frequency
range 30 Hz to 2,000 Hz.

1. Start by carrying out a preliminary measure-

ment with all the pieces of electrical equipment
switched on and make a rough estimate of what
field sources are present in the room. Draw a
sketch of the room. Then measure a number of
points at 1-3 metre intervals by taking readings
in all directions in a circle around you. Write
down the highest value measured at each point
on the sketch. Using an arrow, mark the direc-
tion in which you obtained the value you have
written down. Ideally, note the field levels
towards the ceiling and the floor.

2. Then carry out a measurement with all the

electrical apparatus in the room switched off
to get an idea of the extent of the background
fields in the room. Remember that it is probably
not sufficient simply to switch off the pieces
of apparatus - you will usually need to unplug
them in order to completely eliminate the fields.
In some cases, the background fields can be as
high as the fields from the apparatus in the room.

3. Connect the pieces of apparatus one at a time

and measure the electric fields in the directions
0

°

, 90

°

, 180

°

 and 270

°

 at distances of 30 cm

and 50 cm from the outer edge of the piece of
apparatus in question (see figure) or in the
direction the operator is facing. Summarise the
measurement readings in a report form. An
example of how to fill out a report form can be
found on page 12. You must not subtract the
background values of the electric fields from
the measured values. They should always be
noted as a comparison.

50 cm

50 cm

Overhead view.

Side view.

Cont.

7

References to authorities and organisations

Publication

Publisher/Author

May be ordered from

Magnetic fields and health
risks based on what we
know

The National Electrical
Safety Board

Elsäkerhetsverket

Box 1371
SE-111 93  STOCKHOLM
SWEDEN
Tel. +46 8-519 112 00
Fax. +46 8-519 112 01

Cancer and magnetic fields
in workplace

The Swedish Trade
Union Confederation

LO-distribution
Strömsätragränd 10
SE- 127 35  SKÄRHOLMEN

SWEDEN
Tel. +46 8-796 25 00

Questions and answers about
electric and magnetic fields
associated with the use of
electric power

National Institute of Environ-
mental Health Sciences and
U.S. Dep. of Energy

Superintendent of Documents
U.S. Goverment
Printing Office
WASHINGTON, D.C. 20 402
USA
Tel. +1 202-512-1800

A report of non-ionizing
radiation

Microwave News

Microwave News
Louise Slesin
P.O. Box 1799
Grand Central Station
NEW YORK, N.Y. 10 163
USA
+1 212-517-28000
+1 212-734-0316
[email protected]

Summary of Contents for EnviroMentor Field Finder

Page 1: ...lmers Institute of Technology in G teborg EnviroMentor AB is wholly owned by Radians Innova AB a company which in turn is owned by two of Sweden s most powerful financial institutions This combination...

Page 2: ...fields 7 3 3 Audible signal 7 3 4 Threshold level 8 3 5 Changing the batteries 8 4 Measurement examples 9 4 1 Electric fields 9 4 2 Magnetic fields 10 4 3 Example of report form for measuring magnetic...

Page 3: ...nstrument emits an audible signal that is pro portional to the field strength measured Field Finder measures the electric field in the direction of the measurement surface on the instrument s front sh...

Page 4: ...r does not satisfy the requirements of MPR II but the instrument has been calibrated to produce the same results when measuring electric fields at a distance of 50 cm from a VDU Some measurement objec...

Page 5: ...icroprocessor 10 bit A D converter three dimensional sensor CE assurance Our product satisfies the demands of the Low Voltage and EMC directive as well as the follo wing EMC standards EN 50 081 1 1992...

Page 6: ...eability Traceability means that it should be possible to relate a measurement result to national or inter national standards via an unbroken chain of comparisons Report form B for measuring electric...

Page 7: ...e influenced by objects in the vicinity of the instrument as well as by the person holding it The instrument has to be held still in order to achieve a stable value When me asuring electric fields fro...

Page 8: ...the old batte ries and install new ones 2 x 1 5 V LR6 8 Report forms On the following pages you will find report form templates for measuring electric and magnetic fields Copy the templates fill them...

Page 9: ...e at a time and measure the electric fields in the directions 0 90 180 and 270 at distances of 30 cm and 50 cm from the outer edge of the piece of apparatus in question see figure or in the direction...

Page 10: ...tentials If two plates made of electri cally conductive material are connected to a voltage source one of the plates will have a positive charge while the other will have a negative charge A vol tage...

Page 11: ...he conductor Magnetic fields are usually depicted with the aid of field lines The strength of the magnetic field is constant along the conductor in closed paths around the live conductor In the event...

Page 12: ...asuring equipment Field Finder Object Model Address Room Measured by Date 30 cm 50 cm Comments 0 V m V m 90 V m V m 180 V m V m 270 V m V m Background field V m V m Notes Report 98 2 Field Finder Envi...

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