Deflect 2 degrees?
Hmmm. The earth's magnetic field is around 50uT. To deflect the compass 2
degrees would take 1.7uT at a right angle, right? Therefore, you could set
a level of 1 uT "residual" magnetism for your testing requirement and have
some margin.
With that quantized number, you could then look at materials and find their
residual flux based upon exposure and determine the worst candidates for
this problem.
- Robert -
-----Original Message-----
From: Jacowleff, Bill <[email protected]>
To: 'Price, Ed' <[email protected]>; '[email protected]'
<[email protected]>
List-Post: [email protected]
Date: Friday, October 01, 1999 9:17 AM
Subject: RE: Magnetic Field Testing
>
>Ed,
>
>In response to your question I have a few points,
>
>We use gauss meters (Walker, Magnetic Instrumentation) to measure the
>strength of magnetic fields. A compass on the other hand is measuring the
>direction or polarity of the field.
>which is established when you do expose a material to a magnetic field.
>
>To quantify the effect on the exposed electronic box, you can take a gauss
>reading before and after exposure to the 10 gauss magnetic field.
>
>In the scheme of things, if you were trying to magnetize a material 10
gauss
>is very low strength. We use magnetizers that put out many kilo gauss.
>Very small increments of distance will aide you when you are trying to
avoid
>magnetizing a material.
>
>I do not know of anyway to shield against magnetic fields, but you can
>redirect the magnetic field.
>
>Best Regards,
>
>Bill Jacowleff
>VDO Control Systems
>Airpax Instruments
>150 Knotter Drive
>Cheshire, CT 06410
>Phone: 203 271-6394
>FAX: 203 271-6200
>[email protected]
>
>-----Original Message-----
>From: Price, Ed [mailto:[email protected]]
>Sent: Thursday, September 30, 1999 1:50 PM
>To: '[email protected]'
>Subject: Magnetic Field Testing
>
>
>
>Hi Listmembers:
>
>Today's weird science question is about sensing the strength of a permanent
>magnetic field.
>
>I need to expose an electronics box to a strong magnetic field (10 Gauss).
>Then, after removing the field, I need to approach the box with a "compass"
>and note the separation distance needed to deflect the compass needle a
>couple of degrees. A couple of degrees is pretty hard to read, even on a
>large compass!
>
>The purpose of the test is to make sure that objects exposed to temporary
>magnetic fields do not retain enough field to disrupt a nearby magnetic
>compass.
>
>I am trying to determine what kind of sensor I can use. I have been looking
>at electronic compass modules. Some models provide a DC analog output
>voltage proportional to angle or heading. Has anyone tried this method? Are
>the modules stable enough for this to work? Is there a big problem with the
>placement of the data output lines?
>
>Thanks,
>
>Ed
>
>
>:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
>Ed Price
>[email protected]
>Electromagnetic Compatibility Lab
>Cubic Defense Systems
>San Diego, CA. USA
>619-505-2780 (Voice)
>619-505-1502 (Fax)
>Military & Avionics EMC Services Is Our Specialty
>Shake-Bake-Shock - Metrology - Reliability Analysis
>:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
>
>
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