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Measuring the field direction of a fixed magnet

Measuring the field direction of a fixed magnet

Measuring the field direction of a fixed magnet

I am new to magnets and I have been delegated to create a fixture that can take a fixed magnet and measure the dirction of the field.  The magnet strength can be as high as 1kG.  Currently we do this by attempting to sit the magnet on top of a compass the exact same way everytime and record the angle the needle deflects from the earth's magnetic field.  we would like to go to a digital system that can remove most of the human error from the current system.  I've tried to search on Honeywell's system for a device but everything I've found had specified a +-6G max for full scale.  Any help would be appreciated.

RE: Measuring the field direction of a fixed magnet

Do you just want to find out if you have a North or South Pole?

RE: Measuring the field direction of a fixed magnet

Thank you for your quick responses.  We have a few gauss/tesla meters that can give you the strength of the magnet and a general direction(too much user input for an accurate angle).  I don't need to know the kind of pole, by the way the magnet is approximately a 0.5" washer that is epoxied.  The flux line equipment that cermag has shown is nice but way over kill.  I need something simple, currently we are using a compass and setting the magnet fixture on top of the compass and recording the needle deflection.  I need that sort of device or just a sensor that I can build a micro system around it.        

RE: Measuring the field direction of a fixed magnet

There are magnetic electronic sensors on the market and also a compass module used in robotics (and they are really cheap!).
Search Philips KMZ51 for the sensor and look at http://www.totalrobots.com/acatalog/CMPS01_Magnetic_Compass_Module.html for the module.

http://www.xcalcs.com : Online tools for structural design
http://www.megamag.it : Magnetic brakes for fun rides
http://www.levitans.com : Air bearing pads

RE: Measuring the field direction of a fixed magnet

Which way is the 0.5" washer magnet oriented?  Thru the thickness (height) or across the diameter?

If the magnet is oriented across the diameter, you might want to look at getting the green magnetic viewing paper.  The orientation can clearly be seen and is accurate to within a few degrees.

Or (again, if the magnet is oriented across the diameter), you can buy a cheap dipole magnet with a gap slightly larger than the diameter of the washer magnet, and then place your magnet between the poles.  Your magnet will line up in the direction of the field and then can be marked.  Pretty simple to do and accurate as well.

RE: Measuring the field direction of a fixed magnet

MagMike, the 0.5" is the OD.  
There is a problem with the green magnetic viewing paper  because our magnet is epoxied into a plastic device we would not be able to place the magnet on the paper.  So in order to do this we would have to remove the magnet and doing so usually results in breaking some of the magnet b/c of the epoxy.  And again trying to remove human eyes from the equation to improve the reliability and repeatability of the measuring system is the reason for my question.  I am in the process of reviewing the device from prex and it appears promising.  Has anyone used this device before?  

RE: Measuring the field direction of a fixed magnet

Is the magnetic orientation of the magnet parallel to the diameter or the thickness?  That is what I was asking.

RE: Measuring the field direction of a fixed magnet

MagMike it is parallel to the diameter, sorry.

RE: Measuring the field direction of a fixed magnet

Then just mount it on a motorized rotary stage and drive it around until the field maxes out.  The first magnetometer I cited has an RS-232 interface.  


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