Electricity can power a motor through the phenomenon of electromagnetic induction: when an electric current passes through coils of copper surrounding a permanent magnet, a magnetic field is created and exerts a force on this magnet, thus producing the necessary movement to rotate the motor.
Electromagnetism is the study of the link between electricity and magnetism, two closely connected phenomena. When an electric current passes through a wire, it creates a magnetic field around it: that's the magic (actually, the science!) at work behind electromagnets. Conversely, if you move a magnet near a conductive wire, voila, you generate electric current. This phenomenon of current generation is called electromagnetic induction, discovered by Michael Faraday in the 19th century. In short, electricity and magnetism work together like two sides of the same coin: one can generate the other, and vice versa, which makes many cool inventions possible, from electric motors to the earbuds of your smartphone.
When electrical energy passes through a motor, it creates a magnetic field. This field behaves somewhat like a magnet: it exerts a force on certain parts of the motor, commonly referred to as coils or rotor. This attraction or repulsion causes a mechanical rotational movement. In other words, the current flows through wrapped conductors called windings, and by interacting with the fixed magnets or electromagnets of the motor, these windings start to rotate. This rotary movement can then be used to operate anything you want: fans, wheels, various mechanical systems. In short, we directly transform electricity into movement using simple tricks of electromagnetism.
An electric motor is just a story of magnetic fields. When electric current passes through a coil of wire (called the winding), it creates a magnetic field. This field either pushes or pulls a permanent magnet or sometimes another magnetic field within the motor, and it is precisely this attraction-repulsion that produces rotational movement. In simple terms, electricity enters, the magnetic field activates, it pushes on movable parts called the rotor, which turns in relation to the fixed parts, the stator. And that's how, simply put, electricity is transformed into mechanical motion.
A direct current motor (DC motor) is powered by an electric current that always flows in the same direction, allowing it to easily change speed by simply varying the voltage. This makes it very convenient and precise for applications requiring fine adjustments, such as in remote-controlled toys or robots.
In contrast, the alternating current motor (AC motor) operates on a current that constantly changes direction at a certain frequency. Less complicated to build and maintain, it often powers household appliances like fans or washing machines. However, modifying its rotational speed usually requires more technical know-how, such as the use of frequency converters.
In terms of efficiency, DC motors perform well at variable speeds or low power, while AC motors are robust, durable, less expensive at large scale, reliable over long periods, and ideal for heavy industrial equipment.
Electric motors are all around you: in fans and most household appliances like your washing machine or refrigerator. Many power tools, like drills or circular saws, also operate thanks to small, highly efficient motors.
In industry, electric motors can be found in assembly robots, automotive assembly lines, and in industrial pumps to move liquids or air within factories. Even the elevators and escalators that make your daily life easier operate with these motors. Modern trains, especially TGVs, also use very powerful electric motors to reach high speeds in a super efficient manner.
The first usable electric motor was created in 1821 by Michael Faraday, based on the electromagnetic discoveries of Danish physicist Hans Christian Ørsted.
In modern electric cars, the efficiency of the electric motor often reaches between 85% and 95%, which is significantly higher than that of traditional internal combustion engines (approximately 25% to 40%).
The most powerful electric motor in the world is used to rotate the propellers of huge container ships; some of them boast a power output of up to 80,000 horsepower (approximately 60 megawatts).
The reversal of the rotation direction of an electric motor can be achieved simply by reversing the polarity of the direct current or by changing the sequence of the phases in the case of three-phase alternating current motors.
A battery generally provides direct current (DC). To power a motor designed to operate on alternating current (AC), it is necessary to use a converter called an "inverter." This device transforms the direct current from the battery into alternating current suitable for the motor, allowing it to function properly.
The choice of an electric motor depends on several key criteria such as the supply voltage, the type of available current (direct or alternating), the required speed and torque, the desired energy efficiency, the operating environment (humidity, dust, temperature), as well as space and cost constraints.
The efficiency of an electric motor is the measure of the motor's ability to effectively convert electrical energy into usable mechanical energy. The higher the efficiency, the less electricity the motor consumes to deliver the same mechanical power, which reduces energy losses and operating costs in the long term.
All electric motors generate some heat during operation, but excessive heat can indicate a problem, such as mechanical overload, damaged windings, or poor ventilation. If the motor becomes too hot to touch or emits an unusual smell, it is advisable to have it inspected or serviced to prevent more serious damage.
Alternating current (AC) motors are generally simpler, more robust, and require less maintenance than direct current (DC) motors. They are particularly advantageous on domestic and industrial electrical grids, where alternating current is already available. They can also generate significant power while being relatively lightweight and cost-effective.
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