In order to understand the 101 on Magnetic Field Strength, it's important that you understand the various aspects that are associated with it:
1. Maximum Energy Product
One of the most important variables you are going to come across when measuring magnetic field strength is maximum energy product.
This is going to be one of the key indicators of the magnet's strength. Our point of reference?
The higher the maximum energy product number, the stronger the magnetic field strength
Just like it sounds, remanence is going to be what's left over after removing the external piece that was applied to make it magnetic.
When it's all said and done, the remanence will tell you how strong the magnet's resistance is.
Coercivity is going to be the work required to reduce magnetization to zero. The equation calls for measuring the resistance to demagnetization.
These are going to be measured in Oesterds. (Oe)
4. Pull Strength
A magnet's pull strength is going to be pinnacle when trying to determine how much weight it can hold.
The pull strength is most important to manufacturers whose objective is to provide suppliers with a reliable product that won't give out on their customers.
Usually measured in kilograms, a magnet's pull strength is going to generally be the highest hold power a magnet can contain.
5. Open Circuit Flux Density
Remember how we stated that flux density was measured in Newton-meters (N/m)?
These flux densities are usually measured using Gauss meters and hall probes.
As a point of reference, open circuit flux densities never really go past 6,000 Gauss. Magnetic flux density is known for decreases when the distance between the magnet and metal is increased.
6. Pull Gap Curve
If you ever want a visual representation of magnetic field strength power - a pull gap curve is going to be extremely useful.
Because it measures the point where the pull (kg) and air gap (mm) meet, this chart makes it easy to determine the power of a magnet when it comes in contact with a piece of metal.
If you've ever played with the magnets on your refrigerator, that force you feel when the magnet is close enough to the metal, but not touching is going to be what's measured in the pull gap curve.