Applications of Neodymium Magnets in Electric Motors
What is an Electric Motor?
An electric motor is an electrical machine that converts electrical energy to mechanical energy. Electric motors function based on Faraday’s first law of electromagnetic induction, which states, “Whenever a conductor is placed in a varying magnetic field, an electromotive force is induced. Likewise, if the conductor circuit is closed, a current is induced, called induced current.”
In simple terms, it means that when an alternating current (AC) interacts with a changing magnetic field, they create an electromotive force, also called induced current.
Depending on the motor you’re dealing with, you can power an electric motor using a direct or alternating current source. Direct current sources include batteries and rectifiers, while alternating current sources include power grids, inverters, and electric generators.
While the idea of an electric motor may seem complex or even alien to some, motors are all around us. You will find electric motors in every movable or rotatable object or machine that uses electric current. Motors are in fans, blenders, air conditioning, disk drives, refrigerators, vacuum cleaners, washers, hair dryers, and lots more.
Types of Electric Motors
There are fundamentally three types of motors. They include DC motors, AC motors, and special motors. But then, AC and special motors have sub-types, while DC motors don’t.
DC Motors: DC motors are so named because they are powered by direct current. They are the oldest form of electric motor. They were developed based primarily on Faraday’s theory that electric energy can be converted into mechanical energy by placing a current-carrying conductor in a magnetic field.
AC Motors: Unlike DC motors, AC motors use an alternating current. We have two AC motor types: synchronous and induction motors. There are also two types of induction motors, which include 1 phase and 3 phase induction motors.
Special Motors: Special motors may use direct or alternating current depending on their intended use, but their production is mainly for specialized applications or particular to one industry. They also include custom orders by customers who require them. Special motors include hysteresis, stepper, and servo motors.
Applications of Neodymium Magnets in Electric Motors
In electric motors that use magnets, a permanent magnet, usually a neodymium magnet, is part of the stator. The job of the neodymium magnet is to provide the magnetic field required to rotate the armature or rotor.
In some cases, however, the armature is part of the stator while the neodymium magnet is part of the rotor, but we will not get into that.
Every electric motor has a neodymium magnet that generates the magnetic field. However, a motor’s number of neodymium magnets depends on the motor type and intended use.
Over the years, using neodymium magnets in electric motors has been a common practice. But the growing demand for neodymium magnets in the automotive industry for producing electric vehicles is on a different level entirely.
Electric vehicles, or Battery Electric Vehicles (BEVs), run on electric current rather than the typical liquid fuel like petrol or diesel. Instead of a combustion engine, which requires combustion (burning of fuel) for motive, electric vehicles use electric motors.
Neodymium magnets are used in high-output electric motors, especially those found in electric vehicles, because of their strength, high magnetic coercivity, and resistance to demagnetization forces such as heat.
Another reason neodymium magnets are the industry choice for high-output motors is that they are powerful, even in small sizes. A neodymium magnet is usually stronger than any other magnet type of equal volume.
How Many Neodymium Magnets are There in an Electric Vehicle?
It is estimated that a hybrid or electric vehicle will have anywhere from four to twelve pounds of rare earth magnets like neodymium boron magnets. Because of the variation in design and manufacturer preference, we cannot add a number to the number of neodymium magnets in an electric vehicle. However, neodymium magnets are almost always used in the following parts:
- Heating, ventilation, and air conditioning (HVAC) systems
- Hybrid engine or electric motor
- Sensors, such as those in seats, security, and cameras.
- Window and door control systems
- Disc loader
- Electric vehicle batteries
- Fuel and exhaust systems for hybrids
- Windscreen wipers
Why are Neodymium Magnets Used in Electric Motors?
Three things influence manufacturers’ decisions on choosing neodymium magnets when making electric motors. These three things are size, magnetic force, and heat resistance.
Size: the projection of technology is such that everything to be manufactured in the future comes in compact sizes while maintaining a high-performance level. Hence the best neodymium magnet would be small yet powerful.
Magnetic force: a general rule in magnetism states that the bigger a neodymium magnet, the stronger its magnetic force. And the smaller, the weaker.
This rule leaves manufacturers the only option of looking for neodymium magnets that could generate a compelling force even when small.
Heat: when motors work, heat is one unavoidable by-product. And heat is probably the most notorious demagnetization agent known to man, among other things. So when making electric motors, manufacturers must find neodymium magnets that can maintain their magnetic field even at high temperatures.
Currently, no other neodymium magnet type beats neodymium magnets in these aspects. Even at small sizes, neodymium magnets can pull more than 640 times their weight. Depending on their rating, they can also operate in temperatures up to 220 degrees.
These abilities make them the strongest permanent neodymium magnets and the perfect choice for manufacturers to use in electric motors.
How Do Neodymium Magnets powered Motors Work?
Motors work like any other motor with a neodymium magnet, primarily based on Faraday’s law of electromagnetic induction. While there are several applications of AC motors, we will only explain how DC motors work since they form the basics for the functioning of engines in general.
The parts in a typical DC motor are:
Stator: this is the static unit that contains the winding. It is on the receiving end of the energy supply.
Rotor: this is the rotating part inside of a rotor.
Yoke: the yoke is the external frame that protects the motor’s inner parts from external force.
Poles: these are magnetic fields that fit into and are tightened to the yoke with screws.
Field Windings: these are made with copper wires. They are also known as the field coil. The windings form an electromagnet, and they can generate a filed flux when an electric current passes through them.
Armature Windings: the armature winding is attached to the rotor, and its job is to alter the magnetic field as it rotates.
DC Motor Commutator: the commutator turns the coils on and off, thereby controlling the direction of the electromagnetic field in the armature. It also converts the alternating voltage generated in the armature to DC.
Brushes (for brushed motors): only brushed motors have brushes. They are typically made of carbon or graphite, and their purpose is to bridge the space between the stator and the rotor.
A brushed DC motor has neodymium magnets on its structure, with a spinning armature on the inside.
The neodymium magnets, stationary on the outside, are part of the stator.
The armature contains an electromagnet called the rotor since it rotates.
In a brushed DC motor, when an electric current is run to the armature, the rotor spins 180 degrees. To go any further, the poles of the electromagnet must flip.
As the rotor spins, the brushes make contact with the stator, flipping the magnetic field and allowing the rotor to spin 360 degrees.
A brushless DC motor is a brushed DC motor flipped inside out but canceling the need for brushes to flip the electromagnetic field.
In a brushless DC motor, the neodymium magnets are on the rotor, while the electromagnets are on the stator. And a computer charges the electromagnets in the stator to rotate the rotor a full 360 degrees.
What Types of Magnets are in Tesla Motors?
Tesla Motors uses neodymium magnets for their electric cars, though this wasn’t always the case. Tesla’s move to electric motors using neodymium magnets was announced in 2018, and its first vehicle to use neodymium magnets powered motor was the Model 3 Long Range car.
Tesla’s move to electric motors using neodymium magnets says a lot about the future of the automotive industry and its use of neodymium magnets. That’s because the company has staked its future in manufacturing electric cars. This decision also seemed to have affected the demand for neodymium magnets in the industry.
Where to Get Quality Neodymium Magnets in Bulk?
ROBO magnetic has been manufacturing and supplying custom and standard-shaped neodymium magnets to Europe, America, and Asia since 2006. Our time in the industry has given us the time and ability to refine our process to manufacture high-grade neodymium magnets for standard and personalized applications.
We use cutting-edge technology in our factories, and our engineers and scientists are certified and experienced experts in their field. Our neodymium magnets are ISO 9001:2015 certified, meaning they are of global standards. If you want to purchase high-quality neodymium magnets for educational, industrial, or other personal projects and would like to have them delivered promptly, contact us to discuss how we can help you.
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