Magnet strength is an important factor to consider when choosing magnets for various applications. Measuring the strength of a magnet can help you determine its suitability for a particular use and ensure that it is reliable and effective.
What Is Magnet Strength?
The term “strength” refers to a magnetic pulling force and magnetic field strength.
Pulling force, also known as holding force, is required to pull a magnet away from a ferromagnetic surface (such as iron or steel) with which it is in contact. It is typically measured in force units, such as newtons (N) or pounds (lbs).
Magnetic field strength, on the other hand, is a measure of the intensity of a magnetic field. It is typically measured in units of magnetic field intensity, such as gauss (G) or tesla (T).
While these two types of strength are related, they are not the same thing. Pulling force is a measure of the force required to separate a magnet from a ferromagnetic surface. At the same time, the magnetic field strength is a measure of the intensity of the magnetic field that a magnet produces.
This post will explore different methods for measuring magnet strength and discuss the various units used to express magnet strength. We will also provide tips on choosing the right magnet for your needs based on the strength requirements of your application.
The Different Units Used To Express Magnetic Field Strength
Several units are commonly used to measure magnet strength:
Gauss (G):
This is a unit of magnetic field strength. One gauss is equal to 1 x 10^-4 tesla. It is often used to measure the strength of relatively weak magnetic fields, such as those found in magnets used in consumer electronics.
Tesla (T):
This is a unit of magnetic field strength. One tesla is equal to 10,000 gausses. It is often used to measure the strength of relatively strong magnetic fields, such as those found in MRI machines or particle accelerators.
Oersteds (Oe):
This is a unit of magnetic field intensity. It is often used to measure the strength of a magnet’s coercive force or its resistance to becoming demagnetized.
Amperes per meter (A/m):
This is a unit of magnetic field intensity. It is often used to measure the strength of a magnet’s intrinsic coercive force or its resistance to becoming demagnetized at its Curie temperature.
Mega gauss-oersteds (MGOe):
This is a unit of magnetic energy density. It is often used to measure the maximum amount of magnetic energy stored in a magnet.
Kilojoules per cubic meter (kJ/m3):
This is a unit of magnetic energy density. It is often used to measure the maximum amount of magnetic energy stored in a magnet.
Methods of Measuring The Magnetic Field Strength
Gausseter:
A gaussmeter is a device that measures the strength of a magnetic field in units of gauss (G). It works by detecting the strength of the magnetic field at a given point and displaying the result on a digital display.
Gauss meters are often used to measure the strength of relatively weak magnetic fields, such as those found in magnets used in consumer electronics.
To use a gaussmeter, you hold it near the magnet and take a reading. The gaussmeter will display the strength of the magnetic field in units of gauss.
Fluxmeter:
A fluxmeter is a device that measures the flow of magnetic flux through a given area. It can measure the strength of a magnetic field by measuring the amount of flux passing through the area occupied by the field.
Fluxmeters are often used to measure the strength of relatively strong magnetic fields, such as those found in MRI machines or particle accelerators.
To use a fluxmeter, place it in the area occupied by the magnetic field and take a reading. The fluxmeter will display the strength of the magnetic field in units of flux.
Hall effect sensor:
A Hall effect sensor is a device that measures the strength of a magnetic field by detecting the voltage induced in a conductor when it is placed in a magnetic field.
Hall effect sensors are often used to measure the strength of relatively weak magnetic fields, such as those found in magnets used in consumer electronics.
To use a Hall effect sensor, you place the sensor in the area occupied by the magnetic field and measure the induced voltage. The strength of the magnetic field can then be calculated based on the induced voltage.
Magnetic Field Probe:
A magnetic field probe is a device consisting of a coil of wire sensitive to magnetic fields. It can be used to measure a magnetic field’s strength by measuring the coil’s current.
Magnetic field probes are often used to measure the strength of relatively strong magnetic fields, such as those found in MRI machines or particle accelerators.
To use a magnetic field probe, you place the probe in the area occupied by the magnetic field and measure the induced current. The strength of the magnetic field can then be calculated based on the induced current.
The Different Units Used To Express Magnetic Pull Force
Here are some of the units that are commonly used to express magnet pull strength, also known as holding force:
Newtons (N):
Newtons (N) is a unit of force. One newton is equal to the force required to accelerate a mass of one kilogram at a rate of one meter per second squared.
Pounds (lbs)
Pounds (lbs) is a unit of force. One pound is equal to the force required to accelerate a mass of one pound at a rate of one foot per second squared. One pound is equal to 4.45 newtons.
Kilograms (kg)
Kilograms (kg) is a unit of mass, not force. However, it is sometimes used to express magnet pull strength in the form of the maximum weight that a magnet can hold. For example, a magnet with a pull strength of 50 kg can hold a maximum weight of 50 kg.
Methods of Measuring The Magnetic Pull Force
Pull Test:
A pull test is a simple method for measuring the magnet pull force.
To perform a pull test, you place the magnet on a flat, smooth surface and then try to pull it away from the surface using a force gauge. The magnet pull force is the maximum force required to pull the magnet away from the surface.
This method is simple and inexpensive, but it may not be accurate unless the surface is perfectly smooth and flat.
Force Gauge:
A force gauge is a device that measures force in units of newtons (N) or pounds (lbs).
To use a force gauge to measure the magnet pull force, you place the magnet on a flat, smooth surface and attach the force gauge to the magnet using a spring or cable. You then pull on the force gauge until the magnet comes away from the surface, and the force gauge will display the magnet’s pull force.
This method is more accurate than a pull test but may be more expensive and require additional equipment.
Load Cell:
A load cell is a device that measures force by detecting the deformation of a mechanical element under load.
To use a load cell to measure the magnet pull force, you place the magnet on a flat, smooth surface and attach the load cell to the magnet using a spring or cable. You then pull on the load cell until the magnet comes away from the surface, and the load cell will display the magnet pull force.
This method is more accurate than a pull test or force gauge, but it may be more expensive and require additional equipment.
Choose The Right Magnet Strength
To find the right magnet strength for your specific application, you’ll want to consider the following factors:
- Type of material being attracted: The strength of a magnet needed to hold a given material will depend on the properties of that material. For example, a magnet with a lower holding force may be sufficient to hold a sheet of paper, while a much stronger magnet would be needed to hold a heavy metal object.
- Distance from the magnet: The strength of a magnet needed to hold a given material will also depend on the distance from the magnet. The holding force will decrease as the distance between the magnet and the attracted material increases. A stronger magnet may be needed if the magnet and the attracted material are farther apart.
- Environment: The strength of a magnet needed for a particular application may also depend on the environment in which it will be used. For example, a magnet used in a damp environment may need to be stronger to maintain its holding force.
- Size and shape of the magnet: The size and shape of the magnet can also affect its holding force. For example, a larger magnet may have a stronger holding force than a smaller magnet, and a magnet with a more focused field may have a stronger holding force than a more diffuse field.
Here are a few examples of how the strength of a magnet might be considered in different applications:
- Refrigerator magnets: These magnets typically hold paper or lightweight objects to a metal surface, such as a fridge or filing cabinet. In this case, a relatively weak magnet, such as a ceramic magnet, may be sufficient. The distance between the magnet and the attracted material will be small, and the environment (a dry, indoor fridge) will not be a factor.
- Industrial holding magnets: These are used in various industrial applications, such as material handling and lifting. In these cases, the magnet’s strength will depend on the weight and size of the object being held and the distance between the magnet and the attracted material. A stronger magnet, such as a rare earth magnet, may be needed for heavy or oversized objects or objects that will be held at a greater distance.
- Speaker magnets: Speaker magnets are used to create a magnetic field that interacts with the coil of a speaker to produce sound waves. In this case, the magnet’s strength will depend on the size and shape of the speaker and the desired sound quality. A stronger magnet may be needed for larger speakers or for speakers with a more focused field, while a weaker magnet may be sufficient for smaller speakers or those with a more diffuse field.
- MRI machines: MRI machines use powerful magnets to produce detailed images of the body’s internal structures. In this case, the magnet’s strength will be a critical factor, as it determines the resolution and accuracy of the images produced. MRI machines use superconducting magnets, some of the strongest ones available, with field strengths typically ranging from 0.2 to 3 tesla (T).
I hope these examples give you a better understanding of how magnet strength can be considered in different applications. It’s important to carefully consider the specific requirements of your application when selecting a magnet to ensure that it has the appropriate strength and performance.
Online Magnetic Calculator
If you want to calculate the approximate pull force of a magnet, our online calculator may be able to help. This calculator allows you to enter your magnet’s size, shape, and material grade; then it provides an estimate of the magnet’s pull force based on this information.
An online calculator can be useful for getting a general idea of a magnet’s pull force. Still, it’s important to note that these calculations are only approximate and may not be completely accurate. The actual pull force of a magnet can be affected by various factors, such as the magnet’s specific properties and the attracted material’s characteristics.
If you need a more precise measurement of a magnet’s pull force, our team of experts at the factory can help you.
Related Magnetic Properties
It’s important to note that “strength” is just one of several properties that can be used to describe a magnet. Other properties, such as remanence, coercivity, maximum energy product, and intrinsic coercivity, may also be important depending on the specific application of the magnet.
- Magnetic field strength: The strength of a magnet’s magnetic field can be measured using a gaussmeter. This is a device that measures the strength of a magnetic field in units called gauss.
- Remanence: This is the magnet’s ability to retain its magnetism after removing the magnetizing force. It is usually measured in units of gauss or tesla (T).
- Coercivity: This is the magnet’s resistance to becoming demagnetized. It is usually measured in units of oersteds (Oe) or amperes per meter (A/m).
- Maximum energy product: This is the maximum amount of magnetic energy stored in a magnet. It is usually measured in units of mega gauss-oersteds (MGOe) or kilojoules per cubic meter (kJ/m3).
- Intrinsic coercivity: This is a measure of the magnet’s resistance to becoming demagnetized at its Curie temperature, the temperature at which the magnet loses its magnetism. It is usually measured in units of oersteds (Oe) or amperes per meter (A/m).
Conclusion
When choosing a magnet for your application, selecting a magnet with the appropriate strength is important to ensure that it performs as needed.
If you need magnets for your business or have questions about magnet strength, we invite you to email us or visit our factory and speak with our team of experts. We have a wide range of magnets available and can help you find the right magnet for your specific application. Contact us today to learn more!
