In the application of magnets, magnetic flux or magnetic flux density serve as crucial indicators for assessing their performance, particularly in motors. However, in certain fields such as magnetic sorting and salvage operations, magnetic flux proves to be an ineffective metric for evaluating sorting or adsorption effectiveness. In such cases, magnetic attraction emerges as a more reliable indicator.
Magnetic attraction denotes the weight of ferromagnetic material that a magnet can adsorb. This attraction is influenced by various factors, including the magnet’s performance, shape, size, and adsorption distance. While there is no mathematical formula to precisely calculate the magnetic attraction of a specific magnet, it can be measured using a magnetic attraction measurement device. Typically, this involves measuring the magnetic pulling force of the magnet and converting it into weight. Notably, the suction force of a magnet diminishes as the distance from the adsorbed object increases.
From the measurement results, it was found that:
- The ratio of the weight that magnets of different shapes and sizes can lift to their own weight varies greatly, some are less than 200 times, some are over 500 times, and some can reach over 3000 times. Therefore, the 600 times written online is not completely correct.
- Cylinders or circular cakes of the same diameter can absorb more weight as their height increases, and the suction force is generally proportional to their height.
- Cylinders or circular cakes of the same height (blue cells), the larger the diameter, the greater the weight they can lift, and the suction force is basically proportional to the diameter.
- Cylinders or circular cakes of the same volume and weight (yellow cells) have different diameters and heights, resulting in significant differences in the weight they can lift. Generally, the longer the orientation of the magnet, the greater the suction force.
- The suction force of magnets with the same volume may not be equal, and the difference in suction force may be significant depending on their shape.Conversely, the same applies to magnets that absorb the same weight of ferromagnetic material, which may have different shapes, volumes, and weights.
Regardless of the shape, the length of the orientation direction has the greatest determining effect on the suction force.