Useful Magnet Test Data
Frequently I get asked to take some measurements with my gauss meter to help customers determine which magnet will work best for their situation. I will be adding that data to the website as I obtain it. If you have a need for this information for your project, please ask and I will try to work it into my schedule.
Many websites love to publish the BHmax data for the magnet materials and even though I am an electrical engineer and understand the terms and remember some of the math from 25 years ago, it is hard to take that information and make it useful. My data is intended to be for people needing practical use information. I will continue to expand this data as I develop better testing procedures and acquire better equipment.
The first page is some practical info about gauss levels at various distances above my large magnets - ranging from the 30mm squares by 2mm thick to the 4 inch x 5 inch x 0.5 inch thick.
I had a customer that was interested in how many of the 0.5 inch thick, 4 inch x 6 inch N42 plates were needed to achieve his desired gauss level. So I started with one, then added a second plate and a third. This is the test data at distances until the center reading went below 50 gauss. For 1 plate that was 6.4 inches and for all three it was 9.6 inches away.
4_x_6_N42_0.5_Inch_thick_Plate_surface_gauss
The second set of data was on a large 4 x 6 inch plate that was 3 of the 0.5 inch plates combined for a total of 1.5 inch thick N42 monster magnet. The object was to see how far out from the edge of the magnet the magnetic flux extended. What was interesting was that at various distances above the surface the flux would reverse its polarity as I moved outward.
This page is at the surface
4 inch x 6 inch x 1.5 inch N42 plate
The second page is the same readings but at a height of 0.5 inches above the surface of the magnet
4 inch x 6 inch x 1.5 inch N42 Plate - 0.5 inches above the surface
The second page is the same readings but at a height of 3.0 inches above the surface of the magnet
4 inch x 6 inch x 1.5 inch N42 Plate - 3.0 inches above the surface