What is Magnetic Pull Force
The magnetic pull force is essentially a measure of the force brought into play by magnets whenever they are close to ferromagnetic objects. Typically, it is computed in kilograms or pounds and it determines the attraction or repulsion effect of your magnet.
The Concept of Magnetic Pull Force
Magnets are like invisible hands capable of drawing certain objects to them and grappling them. This ability is heavily influenced by the magnet’s pull force. For attraction to occur, the magnetic poles must be contradictory. That is, the north pole will attract the south pole.
However, if the poles are similar, the magnetic effect you will experience is repulsion. This means that the invisible hands of your magnet will ward off the respective object. If your magnet has superior strength, it is likely to exert a more robust magnetic pull force.
If it is comparatively weaker, its magnetic effect will be relatively weaker. Similarly, if you place your magnet further away from a ferromagnetic object, the pull force will also be inferior. Other various influences can impact the pull force of your magnet.
How to Measure Magnetic Pull Force
Determining the precise pull force of your magnet can help you establish its suitable applications. Luckily, there are numerous instruments you can exploit to compute this.
· Force Gauge
The force gauge is a simple tool that features a magnetic probe and a calibrated spring that gives precise readings of your magnet’s pull force. To use this instrument, you simply need to strap one side of your magnet to the spring as well as one end of a ferromagnetic object.
You will then proceed to pull the spring until your magnet detaches from the gadget. This will give you the precise measurement of your magnet’s pull force.
· Hall Effect Sensor
This instrument gives you accurate measurements of your magnet’s pull force by utilizing the hall effect. This means that your hall effect sensor will initiate a voltage that is perpendicular to the current flow. This gadget is primarily designed to quantify the pull force of magnets deployed in electronic devices since they are non-contact.
Agaussmeter does not necessarily give you measurements of your magnet’s pull force. However, it does give you precise estimations of your magnet’s magnetic strength, which you can then use to calculate its pull force.
· Magnetic Pull Tester
The magnetic pull tester is an advanced instrument revered for accurately measuring the pull force. It features a scale, which reads the pull force, and a mechanical arm that pulls away your magnet from the respective object. The precise degree of your magnet’s pull force is then displayed on its digital screen.
· Bismuth-Lead Force Sensors
This instrument relies on the magnetostrictive concept which looks at the shape transformation of certain objects whenever they interact with magnets. This sensor is highly sensitive meaning that its accuracy is comparatively higher.
The Magnetic Pull Force of Different Magnets
There is a myriad of distinct magnets with each type characterized by different compositions and features. This translates into distinct magnetic pull forces. Underneath, we compare the pull forces of the most commonly utilized magnets.
· Neodymium Magnets
Neodymium magnets are arguably the most robust magnets known to man. This explains their immense strength despite their characteristic small size. Their pull force is comparatively high and this can be illustrated by the pull force of a pot neodymium magnet. For instance, a neodymium magnet with a height and diameter of 30 mm and 50 mm respectively can exhibit a pull force of roughly 100 kg.
· Alnico Magnets
Alnico magnets are quite powerful even though their magnetic strength is comparatively lower than that of neodymium magnets. Their pull force is quite strong, however it depends on the magnet’s size and alloy properties. A small Alnico disk magnet with a thickness of 3mm and a diameter of 10mm is likely to exhibit a pull force of 0.5 to 1 kg.
· Ceramic Magnets
Characterized by their unique elements (strontium carbonate and iron oxide), these magnets are highly revered for their effectiveness and affordability. Their magnetic pull force is moderately strong hence they are often utilized in speakers and refrigerators. For a small ceramic magnet with a diameter of 10mm and a thickness of 3mm, this force is expected to range from 0.2 kg to 0.5 kg.
You can increase or decrease the magnetic pull force of your electromagnet by adjusting current flow. A relatively small electromagnet can exhibit a pull force of 1-5 kg while a relatively big electromagnet may exhibit a pull force of 50-100 kg.
|Magnetic Pull Force (kg) Per Kg of Magnet
|Up to 50 kg
|Up to 10 kg
|Up to 4 Kg
|Over 100 kg
Applications of Magnetic Pull Force
Magnetic pull force is often utilized to alienate varying materials or objects. For instance, you can utilize it to alienate varying components during mining.
This force also means that you can utilize magnets to lift and levitate ferromagnetic materials like iron.
The pull force of magnets also determines the repulsion force of your magnet. This permits the use of magnets in high-speed trains due to the reduced friction.
In laboratories, the magnetic pull force has greatly eased the process of mixing liquids. It allows the deployment of magnets as non-contact stirrers.
A strong pull force allows you to achieve a secure lock hence why magnets are widely incorporated into advanced door locks.
Numerous medical equipment including MRI systems also rely on magnetic pull force to obtain detailed images of internal body organs.
The magnets deployed in speakers and other audio devices also depend on magnetic pull force to generate sound waves. These forces essentially initiate the vibration of membranes ultimately resulting in sound production.
Magnetic pull forces allow you to utilize magnets as holders for clenching metals during essential processes like drilling and welding.
Having accurate measurements of your magnet’s pull force comes in handy in your attempts to optimally utilize your magnet. You can exploit various methods to determine this.
· The Spring Scale Technique
This is one of the most widely utilized methods and utilizes a scale to estimate the magnetic pull force. To utilize this method, you will need a spring scale where you will mount one end of your magnet and one end of a test object. The calibrated scale will then read the force exerted as your magnet pulls away from the test object.
· The Hall Effect Method
To utilize this technique, you will need a hall effect sensor which you will simply install between two magnets. This semiconductor gadget measures the change in voltage in relation to the magnetic field. This ultimately gives you a precise estimation of your magnet’s pull force.
· Bismuth Levitation
For this method, you will need a bismuth plate capable of faintly fending off magnetic fields. To establish the pull force, simply place your magnet above the bismuth plate. Your bismuth levitation sensor will calibrate your magnet’s pull force by estimating the distance at which the lift-off occurs.
· Force Gauge Method
This is one of the most precise pull force measurement methods and estimates the power needed to alienate two magnets. To exploit this technique, you will simply need a force gauge, which is a simple gadget that can be hydraulic or mechanical.
Although there are numerous instruments you can utilize to determine your magnet’s pull force, you can also utilize various theoretical formulas. One popular formula is the Coulomb’s law formula, which states;
F = (μ * m1 * m2) / (4π * d²)
- In this formula, F Stands for the pull force.
- μ stands for magnetic permeability.
- m1 and m2 stand for magnetic dipole moments.
- d² stands for the distance separating your object from the test object.
To use this formula, you will first need to establish the magnetic dipole moment. To determine this value, simply refer to the following formula;
- Ms stands for magnetization.
- V stands for the volume of your magnet.
Secondly, you will need to determine the separation distance, which is essentially the distance between your magnets. With these values, you can proceed to calculate the magnetic pull force of your magnet using the aforementioned formula.
The magnetic pull force is an essential parameter that plays an essential role in determining how you utilize your magnet. Changes in certain factors can increase or decrease your magnet’s pull force. These factors are:
Temperature changes, whether a spike or decline heavily impact your magnet’s pull force. Extreme temperature spikes are likely to deteriorate your magnet’s pull force. For instance, if you surpass your magnet’s curie point, it will lose its magnetic capabilities meaning its pull force will become non-existent.
· Magnet’s Material
The plethora of distinct magnets available today are manufactured from distinct materials. Certain materials boast of superior magnetic properties, which translates into higher magnetic pull forces. These materials include neodymium and Alnico.
· Magnetic Size
A relatively small magnet will exhibit comparatively lower pull forces. A relatively bigger magnet on the contrary will reward you with relatively higher pull forces. For instance, a neodymium magnet with a height of 30 mm and a diameter of 50 mm will have an estimated pull force of 100 kg. A smaller magnet with a thickness of 3 mm and a diameter of 10 mm will have an estimated pull force of 2 kg.
· Magnet Shape
The shape of your magnet determines the concentration and alignment of its magnetic field lines. Shapes such as discs and rings result in comparatively higher magnetic pull forces due to the concentration and even distribution of the magnetic field lines.
· Foreign Magnetic Fields
Once you deploy your magnet within the vicinity of relatively superior external magnetic fields, its pull force will be negatively impacted. This is due to the distortion caused by these foreign fields. They essentially disorient the alignment of your magnet’s magnetic domains.
Magnets are equipped with magnetic capabilities using different methods. These methods achieve different results. If your magnet is highly magnetized, it is likely to exhibit higher pull forces. If the degree of magnetization is relatively lower, its pull force is likely to be inferior.
· Respective Object
The type and composition of the object you intend to attract or repel also have a huge say on the strength of your magnet’s pull force. If the material is highly magnetic, let us say an iron object, the pull force is likely to be higher.
The distance between your magnet and the respective object also impacts the pull force immensely. If you place your magnet further from the object, its magnetic pull force will most likely decrease. This is a consequence of the inverse square law.
· Air Gap
The air gap is the space between your magnet and the test object. This gap is filled with air and its size determines the strength of the magnet’s pull force. A bigger air gap shrinks your magnet’s pull force while a smaller gap increases it.