I have written this science research paper to help people understand more about the electric motors and their operation. The electric motor transforms electrical energy into mechanical energy, which in turn makes motion possible. To better understand electric motors, one should first understand the basics of electric motors operation, electromagnetics.
One can create an electromagnet by running an electric current through a wire which in turn will create a magnetic field. An electromagnet may only be a temporary magnet but it has the same magnetic properties as a permanent magnet. Any magnet creates a magnetic field and this magnetic field will contain two ends or polls, one North and one South. The fundamental law of magnets states that ?Opposites attract and likes repel? and the same holds true with an electromagnet. A simple electromagnet can be created by the use of a power source and a piece of wire as shown in Figure 1. The magnetic field created will be stronger then the magnetic field of the earth, effecting the compass and will cause the needle to move in the direction of this newly created magnetic field.
As current flows through the wire, a magnetic field is created around the wire. Figure 2 shows the circular shape of the magnetic field around the wire as if you were able to look down the end of the wire. The magnetic field itself is invisible, but the magnetic field strength can be measured through the use of special equipment. The magnetic field weakens the further you move away from the wire and will always be perpendicular to the wire and the fields direction depends on the which direction the current if flowing. Since the magnetic field is always circular and perpendicular to the wire, the magnetic field can be increased simply by creating a coil of wire. Figure 3 shows an example of a simple electromagnet by coiling a wire around a nail and connecting it to a power source. The magnetic field is amplified by each loop of wire around the nail.
An electric motor depends upon magnetism to function, to be more specific, electromagnetism. By continuously changing the direction of the electromagnetic field in a motor, we take advantage of the basic magnet principle that ?Opposites attract and likes repel?. This allows an electric motor to rotate.
Upon opening the switch the power is cut to the coil, given that the earth magnetic field generates a torque on the aligned, spinning hydrogen nuclei, they begin to precess around the direction of the earth total field.As the protons precess,the precession produces a time varying magnetic field which induces a small alternating current in the coil such that the frequency of precession of the nuclei is equal to the frequency of the AC current.The proton precession measures the frequency of the oscillatin field and since its equal to the precession frequency of the protons it can be used to determine the strength of the external field.
The force that that turns the armature comes from the magnetic field of the armature trying to line up with the external magnetic field of the stator. This force is called torque. This torque will cause the armature to turn until its magnetic field is aligned with the external field, but no further. How does the armature continue to spin? One of the magnetic fields must be changed so that the armature has to turn again. The armature will spin so long as there is always a torque acting on it. How this is accomplished is what sets each type of electric motor apart.
Magnets are everywhere! They are in telephones, computers, stereos, vacuum cleaners, refrigerators, washing machines, cars, compasses, TVs, VCRs, your doorbell and many other places. The earth itself is also a magnet. The Greeks discovered a mineral over 2,000 years ago that attracted things that were made of iron. This mineral was found in a part of Turkey that was called Magnesia, so they called it magnetite. A magnet is any material that attracts iron or things made of iron. All magnets have two poles, exert force on each other, and are surrounded by a magnetic field.
...which moves a magnet back and forth through a coil of wire to generate electrical current in the wire. To prevent physical wear the piston does not actually touch the inside of the mechanism. This generator is mostly used in NASA projects.
Electric Cars use the energy stored in a battery (or series of batteries) for vehicle propulsion. Electric motors provide a clean and safe alternative to the internal combustion engine. There are many pros and cons about electric cars. The electric vehicle is known to have faster acceleration. They produce no exhaust.
Electric currents produce magnetic fields, they can be as small as macroscopic currents in wires, or microscopic currents in atomic orbits caused by electrons. The magnetic field B is described in terms of force on a moving charge in the Lorentz force law. The relationship of magnetic field and charges leads to many practical applications. Magnetic field sources are dipolar in nature, with a north and south magnetic pole. The magnetic field SI unit is the Tesla, it can be seen in the magnetic part of the Lorentz force law F magnetic = qvB composed of (Newton x second)/(Coulomb x meter). The smaller magnetic field unit is the
The torque developed by the motor is proportional to the product of the armature of the current and air gap flux i.e.
Tesla Motors utilizes an AC induction motor, which was invented by Nikola Tesla in 1888. In the article, How Tesla will change the world, author Tim Urban (2015) explains how an induction motor works:
electricity as the “fuel” instead of gasoline or some other combustible fuel. The electric motor in
Magnets are stones that produce magnetic fields. The magnetic field is invisible, but is responsible for the most noticeable aspect of a magnet: the attraction of a metal object or the repulsion of another magnet. Magnets are used in common everyday household items: credit cards, TVs, speakers, motors, and compasses. A magnets strength is measured by its magnetic moment. (“Magnetism”)
...placing a soft metal core (commonly an iron alloy) inside a coil of wire through which electric current passes in order to produce a magnetic field. The strength and polarity of the magnetic field changes depending on the magnitude of the current flowing through the wire and the direction of the current flow. While there is sufficient flow of current, the core behaves like a magnet; however, as soon as the current stops, the magnetic properties also disappear. Modern devices that make use of electromagnets are the televisions, telephones, computers and electric motors.
Faraday built two devices to produce what he called electromagnetic rotation: that is a continuous circular motion from the circular magnetic force around a wire. Ten years later, in 1831, he began his great series of experiments in which he discovered electromagnetic induction. These experiments form the basis of modern electromagnetic technology.
The phenomenon called electromagnetic induction was first noticed and investigated by Michael Faraday, in 1831. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is a very important concept. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Faraday also investigated the possibility that a current could be produced by a magnetic field being placed near a coiled wire. Just placing the magnet near the wire could not produce a current. Faraday discovered that a current could be produced in this situation only if the magnet had some velocity. The magnet could be moved in either a positive or negative direction but had to be in motion to produce any current in the wire. The current in the coil is called an induced current, because the current is brought about (or “induced”) by a changing magnetic field (Cutnell and Johnson 705). The induced current is sustained by an emf. Since a source of emf is always needed to produce a current, the coil itself behaves as if it were a source of emf. The emf is known as an induced emf. Thus, a changing magnetic field induces an emf in the coil, and the emf leads to an induced current (705). He also found that moving a conductor near a stationary permanent magnet caused a current to flow in the wire as long as it was moving as in the magnet and coiled wire set-up.
Electrical motors function by converting electrical energy into mechanical energy by using the energy stored in the magnetic field (Sarma, 1981). The mechanical energy (torque) is produced when opposing magnetic fields try to lineup. Therefore, the center line of the north pole of a magnetic field is directly opposite to the centerline of the south pole from another magnetic field (Fitzgerald et al., 1981). The opposing magnetic fields in a motor are generated by two separate concentrically oriented components, the stator and a rotor (Figure 2-5).
Synchronous Motor: Supposed in light of the fact that rotor tries to match with the magnetic field in the stator. It has the stator of an induction engine, and the rotor of a dc engine.