Whether to choose a permanent magnet or electromagnet depends on an in-depth understanding of their properties, features are areas of applications.
Today, we will compare some fundamental aspects about these two magnets.
What is a Permanent Magnet?
As long as Curie temperature is not exceeded, these are materials that retain magnetic properties for years, even in the absence of magnetic field or current. Permanent magnets hardly necessitate supplementary energy to exhibit strong magnetic capabilities.
What is Electromagnet?
An electromagnet is a magnetic object featuring a core material, typically iron, wrapped with a wire coil. The magnetic powers of electromagnets can be activated and deactivated by playing with the current flow on the wire coil..
Advantages of Permanent Magnets vs Electromagnets
Advantages of Permanent Magnets
Permanent magnets are quietly embedded in most of the devices we utilize at home and in our workplaces. They offer a myriad of advantages over other magnets and this is why they are indispensable today. Their rewards include:
- Permanence: They are named permanent magnets because they offer indefinite magnetic properties. This makes them the preferred solution for machinery requiring stable and unceasing magnetic forces.
- Unmatched Magnetic Strength: Made from magnetic materials synonymous with robust magnetic capabilities, permanent magnets exert strong magnetic fields. As such, they come in handy in applications demanding strong magnetic powers like magnetic separation.
- Power Efficiency: Permanent magnets have the capacity to create a magnetic field and this stamps out the need for additional energy. This makes them relatively energy-saving compared to electromagnets.
- Precision: Equipped with steady and robust magnetic fields, permanent magnets facilitate the precise operation of sensitive gadgets. For instance, they help MRI machines function with high precision and low magnetic interference.
Advantages of Electromagnet
Electromagnets have greatly impacted a number of industries since their inception. Their uniqueness comes with a broad array of rewards, explaining their broad usage across numerous industries.
- Manageable Magnetic Force: To dictate the strength of an electromagnet, one simply needs to regulate the current flow. This makes electromagnets ideal for applications that necessitate varied magnetic forces at distinct instances.
- Reversibility: Disconnecting the wire coil from a power source results in the disappearance of the magnetic field. Altering the direction of field lines changes the electromagnet’s polarity. For practices that involve constant manipulation of magnetic forces, this feature comes in handy.
- Customization: Electromagnets can be uniquely designed, shaped, and sized to perfectly accomplish various tasks. They can be manufactured in smaller sizes if the intended use scenario demands so or manufactured in an irregular shape depending on the design of the parent machine.
How Limitations of Permanent Magnet and Electromagnets Compare
Limitations of Permanent Magnets
Permanent magnets have proven their indispensability in modern times. However, just like any other man-made object, they exhibit several flaws. These flaws do not bear much significance on their usability but it is essential to be wary of them.
- Temperature Sensitivity: When made to operate under extremely hot or cold temperatures, the performance and effectiveness of permanent magnets may deteriorate. They have a curie point, which when exceeded can result in demagnetization. For example, neodymium permanent magnets begin to lose magnetism at 80°C.
- Brittleness: Permanent magnets are generally made from delicate materials like ferrite. When subjected to physical force or mechanical stress, they can break or crack. This curtails their deployment in certain applications.
- Susceptible to Corrosion: Owing to their parent materials, permanent magnets can rust or corrode under humid environments. This can subsequently result in inferior magnetic properties. However, coating the magnets with a non-corrosive layer can help overcome this challenge.
Limitations of Electromagnets
Despite exhibiting a wide array of benefits, electromagnets are not without constraints. Some of their known limitations include:
- Power Consumption: As we have established earlier, electromagnets must be provided with a power source to generate magnetic fields. Loss of power will instantly deactivate the magnetic field resulting in the loss of magnetic strength. For applications necessitating incessant magnetic forces, generators may be required to serve as energy reserves.
- Limited Range: For an electromagnet to effectively interact with magnetic objects, the objects must be very close to the magnet. This explains why permanent magnets are often deployed in practices necessitating higher ranges at the expense of electromagnets.
- Heat Generation: The current flowing through the wire is often associated with heat generation. Extreme heat is known for shrinking the effectiveness of magnets and in electromagnets, it can lead to damaged wire coils. This is why most industrial electromagnets are often accompanied by cooling systems.
Similarities between Permanent Magnets and Electromagnets
Permanent magnets and electromagnets are two of the most prominent magnet types in use today. Although they exhibit varying magnetic properties, strengths, and weaknesses, they also demonstrate some resemblance.
· Magnetic Poles
All magnets, be they electromagnets or permanent magnets function on the basis of magnetic poles. They have at least two opposite poles, which attract or repel. Identical poles, such as the north pole and an adjacent north pole are repulsive while dissimilar poles attract.
· Magnetic Fields
Permanent magnets and electromagnets alike depend on magnetic fields to interact with external objects. Permanent magnets rely on their inherent magnetic fields while electromagnets create magnetic fields with the aid of external power sources. Irrespective of the magnet type, magnetic fields determine whether an object will be drawn toward the magnet or repelled.
· Attraction and Repulsion
All magnets interact with other objects through attraction or repulsion. However, the nature of the interaction depends on the object’s composition. Objects with ferrous properties are ideally attracted to electromagnets and permanent magnets while objects with non-ferrous properties are repelled.
Differences Between Electromagnets and Permanent Magnets
When comparing electromagnets vs permanent magnets are without a doubt two of the most prominent and effective magnets. Despite exhibiting numerous resembles, these two varieties of magnets demonstrate various differences in certain properties. Beneath, we take a closer look at the distinctions that differentiate permanent magnets from electromagnets.
· Composition and Structure
Permanent magnets are essentially composed of strong materials endowed with ingrained magnetic features. For instance, they can be made of alloys of nickel, cobalt, and iron. The magnetic domains in these materials marshal uniformly resulting in the creation of a permanent magnet. A good example is the neodymium magnets.
Electromagnets, on the other hand, feature a core material, which is often a soft material like iron. The core material is then wrapped with a wire coil. The passage of electric current around the wire initiates the creation of a magnetic field.
· Magnetization
To equip permanent magnets with magnetic properties, they are subjected to processes such as stroking. Alternatively, they are exposed to superior magnetic fields exerted by external magnets. Permanent magnets are ideally magnetized at the manufacturing facility and when utilized as recommended, they hardly lose their magnetic capabilities.
To equip an electromagnet with magnetic properties, simply drive electricity through the wire enveloping the core material. This current is responsible for arranging the magnetic domains uniformly to invoke magnetism.
· Magnetic Strength
Permanent magnets generally showcase strong and stable magnetic forces. This is a consequence of the highly strong magnetic materials they are made from. Additionally, their magnetic strength rarely deteriorates except when they are placed under elevated temperatures or superior, foreign magnetic fields.
Electromagnets, on the contrary, can exhibit varying magnetic strength. Passing stronger currents can elevate their magnetic forces whereas lowering the current amount can shrink their magnetic strength. The ability to manipulate the strength of electromagnets makes them ideal for use in many industries.
· Energy Requirement
After permanent magnets have been magnetized during manufacturing, they hardly necessitate additional power. They are endowed with permanent magnetic capabilities that permit them to generate independent magnetic fields. They can function optimally and infinitely without requiring electricity.
Unlike permanent magnets, electromagnets only generate magnetic fields when electricity flows through the wire coil. Once the flow is halted, the magnetic field is disrupted resulting in demagnetization. For this reason, electromagnets are not ideal for practices demanding stable and never-ending magnetic forces.
· Manufacturing Process
Permanent Magnets are predominantly manufactured in manufacturing facilities and manufacturers commence the process by carefully picking the right magnetic material. After settling on the right materials, the raw materials are prepared expertly to guarantee they meet production standards.
This is followed by the powder mixing process, which is often trailed by the compaction and sintering processes. The materials are then magnetized before being cut into the desired shapes and sizes.
In certain instances, the magnets can be subjected to a finishing process, which attempts to customize the magnet and make it suitable for certain applications.
Electromagnets are relatively easier to manufacture. After selecting a ferromagnetic material as the magnet core, a coil of wire is rounded on the magnetic core material.
Usually, the number of coils can vary and they determine the magnet’s strength. The wire is then linked to a functional power source, which when activated results in the creation of a magnetic field.
· Loss of Magnetic Properties
Permanent magnets are tremendously popular because they barely squander their magnetic properties. When utilized as recommended and subjected to the ideal working conditions, they can retain their magnetic powers indefinitely.
However, overdue exposure to bad conditions like mechanical stress, high temperatures, and superior magnetic fields can lead to magnetism loss.
Electromagnets are a prominent type of temporary magnets whose magnetic properties can be activated, deactivated, or manipulated by adjusting current flow. Unplanned loss of power can result in the loss of magnetic properties hence the need for backup generators when using electromagnets.
· Applications
The key strengths of permanent magnets are robust magnetic forces and permanence. This explains why they are extensively used in day-to-day appliances and applications. They are common choices in loudspeakers, compasses, fridge doors, electric motors, and MRI machines among others.
The primary strength of electromagnets is their controllable magnetic field strength. As such, they are broadly employed in applications that prioritize precision and control over strength. They are perfect for MRI machines, cranes, and door locks among other applications. Furthermore, they are prominent in applications that utilize magnetic forces momentarily.
Conclusion
Permanent magnets and electromagnets play pivotal roles in modern technology. They exhibit similarities and differences in equal measure hence they are distinctly applied in various applications. Understanding the distinction in their magnetic properties and traits is essential as it helps settle on the right solution for the right problem.
