Permanent Magnet Applications
are used in many different applications given their inherent strength
in relation to mass and weight. Electromagnets, because they can be
turned off and on, are used in powerful pieces of equipment and
vehicles, such as magnetic-levitation, or maglev, trains. However,
permanent magnets are also very versatile and strong components of myriad applications as well.How Permanent Magnets Work
A magnet is any material or substance that projects a magnetic field. A magnetic field is a type of vector field that aligns electric charges on a dipolar outlay. Magnets have both a north and south pole, which align to the earth’s magnetic northern and southern poles (and which are not fixed points on the map, but rather varying areas generally located in the regions of the geographic north and south poles). Like poles repel from one another, while unlike poles attract. Ferromagnetic materials, meaning materials which contain some degree of iron, can usually be permanently magnetized, with a catch: if magnets are heated to excessive, known temperatures, they can lose their magnetism. This can be remedied by remagnetising through a process of slowly cooling the magnet.
Types of Permanent Magnet Applications
Scientists use four basic ways to categorize magnets, based on how their magnetic force is used.
Category 1: The magnet’s attraction or repelling force. These applications are the simplest use of magnets. A simple refrigerator magnet is a perfect example—a picture or slogan on a small piece of laminated cardboard with a small bar magnet glued to the back which attracts to a metal refrigerator door.
Category 2: The magnet’s ability to convert electric force into mechanical force.
Electric motors are good examples of using magnets to convert electric energy into mechanical force. While electromagnets are more commonly used for electric motors, permanent magnets
can be used as well. A magnet is placed in a conductive substance, and
then the magnetic field yielded by the magnet turns another piece of
equipment, which rotates the motor rapidly. Category 3: The magnet’s ability to convert mechanical force into electric force.
Generators predominately use this ability. In contemporary times, electromagnets are more often used for power generating turbines, but permanent magnets still play a part. Very simply, two permanent magnets are placed opposite one another, with like sides facing. Their repelling forces rotate a turbine, which then turns a piece of equipment known as an armature. This churning armature generates electricity, which can then be transferred to other purposes.
Category 4: The magnet’s ability to affect ion beams.
Cathode-ray tubes, a type of vacuum tube for focusing electrons, use permanent magnets for aiming purposes. A ring of permanent magnets, alternating north and south poles, is on the end of an electron gun’s yoke, and these ringed magnets can be rotated to focus the beam for better reception or tighter focus.
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