FAQ - Frequently Asked Questions
Is the attraction between magnets as high as the repulsion?
The attraction between magnets is a little stronger than the repulsion. That is due to the alignment of the molecular magnets in the magnet. The attraction as well as the repulsion of magnets decrease significantly with increasing distance.
Table of Contents
When two equal magnets touch each other, the attraction between two unequal poles is 5-10% stronger than the repulsion of equal poles.
That is due to the alignment of the molecular magnets in a magnet. In a single magnet, the molecular magnets are aligned sort of parallel to each other. The more regular the molecular magnets are aligned, the higher is the "strength" of the magnet.
When two equal magnetic poles repel each other, however, the one magnet disturbs the parallel alignment of the molecular magnets in the other magnet. This renders both magnets a little weaker. If you pull them far enough apart, however, they regain their original order and therefore their original strength.
With increasing distance between two magnets, the molecular magnets are hardly impacted by the other magnet anymore. The attraction is then almost equal to the repulsion (see table below).
A numeric example with our large disc magnet S-45-30-N confirms: The attraction (blue) of a magnet is slightly stronger than the repulsion (pink). At a distance of 4 cm, the attractive, as well as the repulsive force, are at approx. 5 kg.
|0 cm||78 kg||72 kg|
|1 cm||30 kg||28 kg|
|2 cm||15 kg||14 kg|
|4 cm||5 kg||5 kg|
x axis= distance [mm]
y axis= force [kg]
blue curve = attraction
pink curve = repulsion
pink curve = repulsion
Note: The indicated adhesive force of 78 kg for this magnet is based on a manual measurement. In our webshop, we publish an official adhesive force of "only" 64 kg. This value was calculated with a mathematical formula. In our webshop, we always specify the lower of the two values to avoid disappointments (see FAQ measuring adhesive force).
If you would like to find more information on the topic of attraction/repulsion between magnets, the research article in the Journal of Magnetism and Magnetic Materials is worth reading. In the article titled "Equations for the approximate calculation of forces between cuboid magnets" researchers at the RWTH Aachen University developed a simple equation for the approximate calculation of forces between magnets.
Practical implicationThe attractive, as well as the repulsive force, decreases quickly with increasing distance. Therefore, only many large magnets make it possible to keep heavy objects, like beds, in levitation via repulsion.
By comparison: Customer project Stool with magnetic suspension uses 8 of our S-45-30-N disc magnets to magnetically support a small chair. This project also illustrates that repelling magnets always need a guide. Otherwise, they will rotate and snap together.