Unlike ordinary magnets, electromagnets heat up. These man made devices do everything a magnet can do and much more. They are particularly useful because it is possible to make them have any desired field strength and become stronger or weaker or even turned off.
Basically, electromagnets are coils of wire wrapped around a metal core, which in turn are connected to a battery. Although they are easy to make, they can have a problem with overheating if given more voltage than their wires can withstand. Fortunately, with careful design, this problem can be avoided.
As mentioned, it is possible to avoid heating of electromagnets. To do this, you can multiply the diameter of the electromagnets, i.e. the distance from one side of the coil to the other, by 3.14. Then, multiply this figure by the number of turns on the coil you are using.
This will give you the length of cable your electromagnet will use. If you measured the diameter in inches, the length will then be in inches. If the measurement was in centimeters, the length will be in centimeters.
Then, dwell the wire gauge resistance chart and select a random wire gauge. Look at how many ohms of resistance the wire gauge has per foot, meter, or your chosen unit of measure. Multiply this by the length of cable your electromagnet will require. The resulting figure will be the number of ohms of resistance your wire will have in that meter.
Next, divide the voltage of the battery you intend to use by the resistance of the cable you are considering. The result will be the current that will flow in that cable when it is connected.
You can compare this figure to the maximum current rating for that caliber wire on the current rating wire gauge chart. If the current your electromagnet will draw is greater than the maximum for which the meter is rated, do the calculations again, but with a smaller gauge wire.
The lower the gauge, the wider the cable and the more current it can carry. Repeat this process until you find a meter that safely transmits the current your device will produce without overheating.
You have to keep in mind that:
The more coils your electromagnet has, the stronger the electromagnet will be.
The higher the battery voltage, the stronger the electromagnet. The width of your electromagnet depends on what you want your electromagnet to do.
When any electromagnet gets hot enough, the magnetism disappears.
The absence of heat produces a super magnetic effect.
Generally speaking, yes. Electromagnets are in many of the everyday objects that we hadn't even noticed could have one inside. Among their most frequent uses, and in which their presence could not be replaced by any other element, are electric motors, which usually heats the electromagnet very frequently.
There is a diversity of uses for electromagnets in the industrial sector, as well as in robotics. Electromagnets are also used to lift heavy weights of metals such as in scrapyards.
To clarify all your doubts about why electromagnets heat up, at IMA we help you choose the type of magnet that best suits your needs. If you have any doubt, ask us.
Ferrite magnets are permanently attached and have good mechanical properties that allow them to be cut into different shapes and sizes. These magnets are cut with diamond tools, while standard drills and wire spark erosion techniques do not work because they are electrically insulating.
This occurs because the current does not pass through them due to their extremely high electrical resistance, characteristic from which they are known by their other name: ceramic magnets.
Ferrite magnets are manufactured by wet or dry pressing and sometimes by extrusion. Wet pressing provides stronger magnetic properties, e.g. C8 ferrite. Dry pressing provides better dimensional tolerances, such as C5 ferrite.
In addition, the magnets are sintered to fuse the powder and then processed to the final shape. The extrusion method can be applied to produce arc segment shapes that are then cut lengthwise. Sometimes new tools are required to produce ferrite magnets if existing tools do not allow the desired shape to be produced. Typical tolerances for ferrite magnets are +/- 0.25 mm, although +/- 3% is also used.
When ferrite magnets heat up, their high intrinsic coercivity really improves (improving demagnetization resistance) making them extremely popular in motor and generator designs.
In fact, the use of ferrite magnets in loudspeaker applications is very common, precisely because only these types of permanent magnets become noticeably more resistant to demagnetization when heated.
Ferrite magnets have a positive temperature coefficient of intrinsic coercivity (it changes in +0.27% / degrees C with respect to the environment) and only ferrite expresses this characteristic that much. However, the magnetic output drops with temperature (it has a negative induction temperature coefficient of -0.2% / ambient degC). The end result is that ferrite magnets, or ceramic magnets, can be used at high temperatures with very few problems.
Ferrite magnets can be used up to +250 degrees C (and in some cases up to +300 degrees C), making them ideal for use in electrical machines and most high temperature applications. At sub-zero temperatures, for example, less than -10 to -20 degrees Celsius, ferrite magnets may begin to show reduced tensile strength. That is, the temperature and degree of attenuation depends on the shape of the magnet and are application specific. In most applications, the operating temperature is not low enough for this effect to occur.
This is because if its temperature coefficient of +0.27% / degrees C of intrinsic Coercivity - the Hci drops as the magnet cools. The ferrite can demagnetize if placed in a too cold environment, but it is the total design of the magnetic circuit that determines how cold the magnet must be before any impairement is noticed.
Among the main features of ferrite magnets is the fact that it is possible to cut them without losing magnetism, while they can be used in a number of applications, including:
Speakers
Hard Disk Drives
Sensors
ABS Systems
Magnetic Shock Absorbers
Retainers
Engines
Alternators
Microphones
Brakes
If you have doubts between buying a neodymium magnet or ferrite magnets, at IMA we help you choose the type of magnet that best suits your needs. If you have any questions, please ask us.
Electromagnets in industrial robotics are very commonly used, especially in the last decade. They are often mounted on robotic tools used to lift ferromagnetic materials, such as steel sheets or scrap metal. Another commonly used industrial component is the inductive proximity sensor, which is used to detect if a metal object is close to the sensor.
These two components are sometimes used together and sometimes as parts of robotic tools, where the sensor is used to detect the object that the electromagnet will lift. This configuration gives the combined tool a distinct advantage over a similar tool, but without sensors, in that it can compensate for changes in its environment. It can be used, for example, to compensate for individual tolerances when working with a large number of objects.
When we talk about the abundance of electromagnets in industrial robotics, we mean that they are present in robotic arms used in a factory environment for manufacturing applications. Traditional industrial robots can be classified according to different criteria, such as the type of movement (degrees of freedom), an application (manufacturing process), an architecture (serial or parallel) and a brand. Then, there is also a new qualifier for industrial robots that may or may not be collaborative.
Electromagnets are in all of the industrial robots mentioned above and there is a wide variety of them. For example, a painting robot will require a small payload of electromagnets but a large range of motion and will be explosion-proof. On the other hand, an assembly robot will have a small work space but it will be very precise and fast, so it requires more attention in working loads with electromagnets. Depending on the target application, the industrial robot will not only have a specific type of movement, but also the use of electromagnets in industrial robotics is used in different ways.
But one important thing to keep in mind is that, in addition to electromagnets, in robotics there is also the use of permanent magnets because of their difference with electromagnets, especially to secure components in the ground. In this way, the industry saves energy consumption and receives more strength at the time of underwriting for issues related to size and weight.
In some cases, electromagnets in industrial robotics are used to control industry remotely, but this requires a large magnet, which consumes a considerable amount of energy, so it is not as common, at least not as much as the use of electromagnets in robotic arms.
Among
the advantages that the use of electromagnets has in industrial robotics, it is
worth highlighting the fact that the applications can be switched on and off,
according to the needs.
The coils of electromagnets are generally made of copper wire, because copper is an excellent conductor of electricity.
Electromagnets in industrial robotics also have the following applications:
An electric bell. The electromagnets make the hammer vibrate from side to side, ringing the bell.
An electric lock. When answering an incoming phone, the door can be unlocked from an upstairs floor. An electromagnet pulls the bolt to open it. Turn it off and the bolt will come out backwards.
A crane. A crane and a lifting magnet can lift tons of steel without hooks and ropes, which is very similar to the function they have in industrial robots.
A surgeon's tool. An eye surgeon may remove pieces of steel from a patient's eye with an electromagnet, increasing the current until it pulls enough to gently remove the metal.
Microsurgery. The researchers are working on electromagnets that can move micro- robots around the body to perform the surgery without opening the patient.
At IMA we offer our customers different types of magnets, whether neodymium, ferrite, samarium, alnico or plastic, but also some models of electromagnets, among which we highlight the circular, rectangular and drive electromagnets.
When deciding to buy a type of magnet we must know the use we are going to give it. That use will determine the purchase, choosing the magnet that best suits our needs, since, as in everything, there are some magnets that will fit more than others to a particular type of space. It is not the same to buy a magnet that must withstand high temperatures than another that does not. Just as it is not the same to do us with a magnet that we are going to use in exteriors that with another one whose use is inside our house or work.
Neodymium magnets consist of a type of rare earth material, and we can indicate that it is a special material. If we combine it with iron or boron we can create the most powerful magnets today. On the other hand, due to its nickel and copper coating, it obtains a very beautiful surface of a silver colour, so that its use in interiors is perfectly compatible with home decoration. The clamping force is so powerful that it can be used in confined spaces. But as we
shall see, Samarian magnets also belong to the rare earth group and coincide in many things, although there are some, as we will see below, that make them different.
Samarium Magnets are among the strongest and are mainly used in generators, electric motors, sensors and measurement technology. In highly technological processes, the samarium magnet is indispensable.
But before continuing we must warn that the Samarium magnet is a special permanent magnet and we must highlight its high performance. As already mentioned, Samarium magnets belong to the rare earth family. Samarium, in combination with cobalt, is an alloy used primarily in the production of permanent magnets.
Until the mid-1970s, these magnets were mainly used when the energy density of ferrite magnets was no longer sufficient. But while ferromagnetic magnets are very susceptible to temperature, rare earth magnets reach operating limits of up to 450°C. Just as these magnets have a high corrosion resistance.
Possibly, corrosion is among the main differences between the two. The Samarium magnet, even if uncoated, is highly resistant to corrosion and also to acids. In fact, we can indicate that Neodymium magnets were invented in the mid-1980s as an alternative to Samarium magnets. But its distrust of corrosion and the need to be treated on its surface, clearly indicate the superiority in this aspect of Samarium.
Today Samarium magnets are mainly used in the motor industry. They can be found in electric, direct current, linear and servo motors, as well as in brake technology. Also in sensor technology.
In general we can say that both rare earth magnets are very versatile. And some of its properties such as flexibility, functionality and precision stand out, which makes us able to give it almost unlimited uses. There are many fields of application in which we can see your application.
Therefore we can say that corrosion resistance is the main difference with the Neodymium magnet. While both share many other characteristics such as energy density and also the perfect use at high temperatures.
Neodymium magnets are made of a combination of iron, boron and neodymium and, to ensure their maintenance, handling and care, we must first know that these are the strongest magnets in the world and can be produced in various forms, such as discs, blocks, cubes, rings, bars and spheres.
The coating of neodymium magnets made of nickel-copper-nickel gives them an attractive silver surface. Therefore, these spectacular magnets serve perfectly as gifts for craftsmen, fanatics and creators of models or products.
But just as they have a powerful adhesive force and are capable of being produced in miniature sizes, neodymium magnets require specific maintenance, handling and care in order to keep them in optimum working order and avoid accidents.
In fact, following the following safety and use guidelines could prevent potential injury to people and/or damage to your new neodymium magnets, because they are not toys and should be treated as such.
May cause serious bodily injury
Neodymium magnets are the most powerful rare earth compound commercially available. If not handled properly, especially when handling 2 or more magnets at once, fingers and other parts of the body may be pinched. The powerful forces of attraction can cause neodymium magnets to come together with great force and catch you by surprise. Be aware of this and wear proper protective equipment when handling and installing neodymium magnets.
Keep them away from children
As mentioned, neodymium magnets are very strong and can cause physical injury, while small magnets can pose a choking hazard. If ingested, the magnets can be joined together through the intestinal walls and this requires immediate medical attention because it can cause serious intestinal injury or death. Do not treat neodymium magnets the same way as toy magnets and keep them away from children and babies at all times.
May affect pacemakers and other implanted medical devices
Strong magnetic fields can adversely affect pacemakers and other implanted medical devices, although some implanted devices are equipped with a magnetic field closure function. Avoid placing neodymium magnets near such devices at all times.
Neodymium powder is flammable.
Do not machine or drill neodymium magnets, as neodymium powder is extremely flammable and may present a fire hazard.
May damage magnetic media
Avoid
placing neodymium magnets near magnetic media, such as credit/debit cards, ATM
cards, membership cards, discs and computer drives, cassette tapes, video
tapes, televisions, monitors and screens.
Neodymium is fragile
Although most magnets have a neodymium disc protected by a steel pot, the neodymium material itself is extremely fragile. Do not attempt to remove the magnetic disk as it will probably break down. When handling multiple magnets, allowing them to come together tightly can cause the magnet to rupture.
Neodymium is corrosive.
Neodymium magnets come with a triple coating to mitigate corrosion. However, when used underwater or outdoors in the presence of moisture, corrosion can occur over time, which will degrade the magnetic force. Careful handling to avoid damage to the coating will prolong the life of your neodymium magnets. To repel moisture, keep your magnets and cutlery.
Extreme temperatures can demagnetize neodymium.
Do not use neodymium magnets near extreme heat sources. For example, near a rotisserie, or the engine compartment or near your car's exhaust system. The operating temperature of a neodymium magnet depends on its shape, grade and use, but may lose strength if exposed to extreme temperatures. The most common grade magnets withstand temperatures of approximately 80 °C.
If you want to know more about this subject, we invite you to know the uses of neodymium magnets in a motor, as well as the industrial and technological applications of neodymium magnets.
Today, it is very common applications of neodymium magnets in electric motors has increased considerably, especially due to the growing demand that exists with electric cars in the global automotive market.
Neodymium magnets are permanent magnets produced from a composition of neodymium, iron and boron. The material remains the strongest type of rare earth permanent magnets currently available.
In fact, in the past it was safe to find neodymium
magnets in products such as hard drives, microphones, speakers, headphones and
magnetic bearings, among others, but now, neodymium magnets in electric motors
are even more common than they seem.
Electric motors and revolutionary new technologies are at the forefront and magnets have a vital role to play in the future of the world's industry and transport. Neodymium magnets act as the stator or part of a traditional electric motor that does not move. The rotors, the moving part, would be a moving electromagnetic coupling that pulls the pods along the inside of the tube.
In all cars and in future designs, the amount of electric motors and solenoids is well in double figures. They are found, for example, in:
Electric motors for windows.
Electric motors for windscreen wipers.
Door closing systems.
One of the most important components in electric motors are neodymium magnets. The magnet is usually the static part of the motor and provides the rejection power to create a circular or linear motion.
Neodymium magnets in electric motors have more advantages than other types of magnets, especially in high performance motors or where reducing size is a crucial factor. Bearing in mind that all new technologies aim at reducing the overall size of the product, it is likely that these engines will soon take over the whole market.
Neodymium magnets are increasingly used in the automotive industry, and became the preferred option for designing new magnetic applications for this sector.
So neodymium magnets are used in various types of motors, such as the high-performance motors found in electric vehicles, the use of which has increased rapidly. The automotive world has recently developed a new type of neodymium magnet, which uses significantly less neodymium and can be used in high temperature conditions.
This new type of magnet is useful for expanding the use of engines in various areas such as automobiles and robotics, as well as for maintaining a balance between supply and demand of valuable rare earth resources. The automotive industry, however, is working to further improve performance and evaluate application in products while accelerating the development of mass production technologies, with the goal of achieving adoption in all engines used for various applications, including automobiles and robotics.
In electric motors, neodymium magnets perform better when the motors are smaller and lighter. From the engine that spins a DVD disc to the wheels of a hybrid car, neodymium magnets are used throughout the car.
A neodymium magnet with a low degree of coercivity may begin to lose strength if heated to more than 80°C. High coercitivity neodymium magnets have been developed to operate at temperatures up to 220°C, with little irreversible loss. The need for a low temperature coefficient in neodymium magnet applications has led to the development of several grades to meet specific operational requirements.
If you want to know the uses of neodymium magnets in a motor, stay informed with the magnet world articles that IMA offers you.
The food sector is one of the most advanced and industrialised sectors of all or, at least, so in the most industrialised countries of Europe and North America. The techniques that we see in other industries such as automotive assembly lines also have their application to the production lines of different food products of all kinds, from meat and fish to processed foods such as biscuits and chocolates.
In all these phases of the development of the production chain, one of the fundamental roles of this whole process is played by the magnets used in the food sector. Thus, we can see that there are different types depending on the results sought, which is why in this article we want to explain what each of them consist of and what are the exact uses given to them.
It should be noted that the involvement of magnets in
the food sector goes back many decades and goes far beyond this short list;
they are found in almost every machine that is used during the treatment or
processing of food as a component. However, we want to highlight here the uses
that are given to the magnets in a particular way citing and explaining some of
the models of magnets for food that we have in our catalog.
Magnetic grids: These magnets from the food sector are used to purify any type of particle that may be found in foods of a granular or dusty nature, such as, for example, flour and rice. Thus, these magnetic grids can be placed in different parts of the production chain depending on what you are looking for, although normally these magnets in the food sector are located at the entrance of pipes, channels or hoppers eliminating any ferrous material that may be.
Magnetic filters: Like grills, magnetic filters have a very similar use, since their purpose is to filter magnetic impurities that may be at the exit of a conduit.
Magnetic drums: In the food industry, in addition to filters and devices responsible for eliminating or reducing impurities, magnetic drums also stand out; always responsible for protecting the different machines involved in food processing, packaging or treatment.
Special P.E.F. plate: This type of special magnet is widely used in the food industry. It is generally placed on a conveyor belt or on inclined channels to act better on the different products. In addition, this device is made with large ferrite magnets that produce a large magnetic field of great strength. These special P.E.F. plates are used above all in the protection of mills, rows and any type of machinery.
Magnetic rollers: This is perhaps the most well-known type of magnet in the food industry, as it has a very characteristic shape. Magnetic rollers are usually located in production lines and aim to remove iron particles that could circulate through it. In addition, these types of magnets, due to their high demand, come in a large number of different sizes and, in addition, can be ordered with specific measures to meet any type of special need.
As we can see, magnets are a fundamental part of the food industry since they play a very important role in guaranteeing the salubrity, hygiene and quality standards of food throughout the whole process.
Knowing the characteristics of both magnets and their main features, their conditions and possibilities, their disadvantages, will allow us to decide for the use of one or the other according to our needs before deciding for a specific type. In addition, we will be able to see during this article, the main utilities that are being given to one and another type of magnet at the present time.
Alnico magnets consists mainly of aluminium, nickel and cobalt. This type of magnet, increasingly used and with characteristics that make it highly recommendable for certain actions and in certain sectors, has a high remnant induction. However, we must affirm that it has a low coercitivity.
Alnico's magnets have stability at extreme temperatures, maintaining, even in the worst conditions, their characteristics and magnetization at temperatures between -250ºC and 425ºC. The Alnico magnet has a high magnetic induction and we can see its use, above all, in measuring devices and magnetic field detection systems.
However, we must not forget that Alnico is a rather fragile material and can only be handled during the casting process, not after this process, so it is not manipulable once melted.
The orientation of the material is carried out during the heat treatment, so that a magnetic field with the defined magnetization direction can be achieved. The state and the way it behaves in the face of oxidation is good.
Samarium magnets, and also Neodymium magnets, are known as rare earth magnets and are, in all probability, the most advanced of the magnetic materials we have today.
Today they are the most powerful magnets on the market. They have a high coercitivity and a high remanence, which allows to design new models and their introduction in new fields for their application, above all, in limited spaces, with little space, or where a high magnetic field is necessary.
However, we must warn that the temperature can condition us when using these magnets, although we have a wide range ranging from 200 º C to 350 º C. These magnets do not present any oxidation problems either. Moreover, we can say that these types of magnets have a high resistance to corrosion. Cobalt-Samarium magnets withstand and operate at temperatures below 0°C.
Samarium Magnets are among the strongest and are mainly used in generators, electric motors, sensors and measurement technology. In highly technological processes, the samarium magnet is indispensable. It is a special permanent magnet and we must highlight its high performance.
As already mentioned, Samarium magnets belong to the rare earth family. Samarium, in combination with cobalt, is an alloy used primarily in the production of permanent magnets.
Today Samarium magnets are mainly used in the motor industry. They can be found in electric, direct current, linear and servo motors, as well as in brake technology. Also in sensor technology.
In general we can say that both rare earth magnets are very versatile. And some of its properties such as flexibility, functionality and precision stand out, which makes us able to give it almost unlimited uses. There are many fields of application in which we can see your application.
For all this we can say that the resistance to corrosion, as well as the density of energy and its perfect use at high temperatures are its main characteristics and what makes it different from many others.
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