Learning just how frequently you work with electric motors on a regular basis may surprise you. From using your computer, to starting up your windshield wipers, running the washer and dryer, or blending a smoothie, the everyday world runs on electric motors – using DC (direct current), and AC (alternating current) to create the mechanical motion all around you.
If you’ve ever attended a science class that covered the basics of electricity – the chances are that you will have learned about electromagnetic force – an energy created by the combined power of magnetism and electricity. In simple terms, an electric motor is an instrument for channeling that force into energy that powers a wide variety of machines. Of course, in order to create that energy – an electric motor uses a number of complex components that are capable of manipulating the power of an electromagnetic field – but, how exactly do they work?
How Electric Motors Function
At a basic level, an electric motor creates motion using magnetism. The idea is that you run electricity through a system, and that electricity combined with the movement of magnets delivers rotational power to charge a machine. Of course, behind the surface, the concept is a little more complex than this. Electric motors include the use of an armature – or electromagnet – constructed using an iron bar wrapped in highly conductive coiled wire. As electricity moves through the armature, that coiled wire delivers a magnetic field that interacts with the magnetic field of the magnet within the electric motor – causing the armature to spin.
The direction in which the armature spins will depend on the placement of the field magnet, and the battery leads within the motor. If the electricity moves to the positive end of the field magnet from the positive end of the battery end, the repelled armature will spin in one direction. However, if electricity flows to the negative end of the field magnet from the positive end of the battery lead, the magnet will attract the armature – causing it to spin in the other direction. Similarly, the “torque”, or power that the motor can produce will depend on the length of the wire within the stator (magnet). The longer the wire is, the stronger the magnetic field will be.
How DC and AC Electric Motors Work
In order for an electric motor to work, and continue working, the coil of wire around the magnet needs to keep turning continuously – therefore generating energy. In order to do this, there must be an available power source, and in regards to electric motors, there are two basic solutions available: AC, and DC. On the surface, both motors use the same power taken from the electromagnetic field, but they work somewhat differently.
For instance, in a direct current motor (DC), a magnet, or stator, is fixed on the outside, whereas the armature is located inside to carry the current. As the energy current moves through the wire on the armature, an electromagnet emerges with a polarity opposite to the external magnet, delivering a repulsion that forces the armature to begin rotating. For that rotation to continue, a force must maintain the opposing magnetic field. Without assistance, after partial rotation, the electromagnet would stick in place as the opposite poles come into contact and attract each other. Flipping the current often involves the use of a commuter, and tiny brushes made of metal, or carbon. With the use of the commuter and brushes, the poles of the magnet can twist, ensuring that the north pole of the fixed magnet remains consistently in line with the electromagnetic North Pole.
Contrastingly, alternating current (AC) electric motors, use a primary and secondary magnet to allow for automatic change of polarity. Most of the time, AC motors don’t permit currents to move through the armature coils through direct supply, as instead, the current is created by the movement of the coils. The primary magnet of an AC motor attaches to a generator for energy, whereas the secondary uses induction to receive energy from the primary without contact. The coils receive energy in sequence to deliver a magnetic field that rotates around the external motor – keeping the system in motion.
Electric Motors Are Everywhere
When the peripherals of an electric motor work together in the right way, these systems can be compact enough to command tiny devices, or large enough to facilitate movement in huge vehicles. As such, many experts consider electric motors to be one of the most effective and efficient ways to produce mechanical energy.