MadSci Network: Engineering |
Authur, To understand how electricity gives a motor energy, you must take a look at the properties of electricity and magnetics and the common bonds/reactions between the two. First, lets put together a short definition for electricity: Electricity is the accumulation or movement of charged particles. All matter solid, liquid or gas is made of particles, some of which carry an electrical charge, called electrons. An electric current is the flow of negatively charged "free" electrons through a material. The electrons always flow toward the positive terminal in a circuit. Magnetism is the magnetic force which is also produced by the motion of charged particals such as electrons .This shows you the close relationship between electricity and magnetism. The electron motion generated force creates a magnetic field, you can visualize this as looking similiar to the expanding ripples seen when you drop a rock in water. This magnetic field can influence other magnetic materials without physically contacting them. Hold a magnet close to your refrigerator, feel the pull, or rub a balloon on your head and see how it will stick, attract, to the wall in your room. These are both examples of magnetism which can both attract and repel surrounding matter. The close relationship between electricity and magnetism is what's in- volved in the study of electromagnetic theory. Some of the discoverers were Petrus Peregrinus, William Gilbert, Charles Coulomb, Hans Oersted, Andre Ampere, Dominique Arago, Michael Faraday and James Maxwell. I recommend some reading on their discoveries for you to get a better understanding of reactions taking place. In this area of electromagnetics it is seen that a conductor passing through a magnetic field will produce an electric current or conversely (most importantly for a motor) if a current is passed through a conductor which is in a magnetic field, a mechanical force is produced. Knowing these relationships we can now make the statement that an electric motor creates movement by placing current carrying coils in a magnetic field. A common motor, called an universal motor, is made up of the 3 major components. A stator, rotor and brushes. The stator, an electromagnet, creates the magnetic field. The rotor consists of several coils of wire. Brushes feed one coil with current and its resulting magnetic field interacts with that of the stator causing the rotor to turn slightly. As each coil is fed in quick succession, the rotor spins. Thus you have taken electricity, converted it to electromagnetics, which transferred some of its energy to the movement of the motor shaft. There are many types of motors each with its own design and means of utilizing this interaction of forces. Such as the computer you're using right now most likely has a stepper motor to drive the hard disk. I hope my conversation has helped you understand a little more about motors and their use of electricity. Take some time to look up the people I mentioned plus some others and keywords. Remember questions like yours is what leads to the great inventions, but only if you seek out the answers. Words: Thomas Edison Electrons Rotor Nikola Testa Electric Current Brushes Charles Steinmetz Circuit Electricity Magnetic Field Magnetics Electromagnetic Charged Particles Conductor Atoms Stator Thanks for writing and keep asking questions. Greg