Tips to get the Perfect Electric motors
2008-08-07

                                                                                            Tips to get the Perfect Electric motors          With the rapid development of our society, more devices that should have the capacity of converting electricity to mechanical work are becoming a part of our life. As electric motors’ basic functions, electric motors are generally found in household appliances such as fans, refrigerators, washing machines, pool pumps, floor vacuums, and fan-forced ovens.          Electric motor’s working principle is not very complex.          The electric motor is based on the principle of electromagnetism and uses the Lorentz law. When current flows through a wire it produces a magnetic field. The right hand rule is used to describe the magnetic field. The right-hand rule is used to find the direction of the force. When the thumb points in the direction of the current and the fingers point in the direction of the external magnetic field, then the force experienced by the conductor is in the outward direction from the palm.          An electric motor has a rotating part called the rotor and a stationary part called the stator. Electromagnets called poles are wound on the frame called the armature. When current is passed, the rotor rotates due to the torque generated by the wires and the magnetic field. The rotation is transferred to a shaft which transfers its rotation energy to any device that is attached to it.         There are several major design and manufacturing standards covering electric motors: • International Electro technical Commission: IEC 60034 Rotating Electrical Machines         The International Electro technical Commission (IEC) is a not-for-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electro technology". IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology and marine energy as well as many others. The IEC also manages conformity assessment schemes that certify whether equipment, systems or components conform to its International Standards. The IEC publishes standards with the IEEE and develops standards jointly with the International Organization for Standardization (ISO) as well as the International Telecommunication Union (ITU).        Today, the IEC is the world's leading international organization in its field, and its standards are adopted as national standards by its members. The work is done by some 10 000 electrical and electronics experts from industry, government, academia, test labs and others with an interest in the subject.        The IEC is made up of members, called national committees, and each NC represents its nation's electro technical interests in the IEC. This includes manufacturers, providers, distributors and vendors, consumers and users, all levels of governmental agencies, professional societies and trade associations as well as standards developers from national standards bodies. National committees are constituted in different ways. Some NCs are public sector only, some are a combination of public and private sector, and some are private sector only. About 90% of those who prepare IEC standards work in industry. • National Electrical Manufacturers Association (USA): NEMA MG 1 Motor and Generators        The National Electrical Manufacturers Association or NEMA is a U.S.-based association, which was created on September 1, 1926, when the Associated Manufacturers of Electrical Supplies and the Electric Power Club merged. It is headquartered in Roselyn, Virginia. It sets many common standards used in electrical products among its over 400 members.        NEMA has established a range of standards for electrical equipment enclosures. For more detailed and complete information, see the NEMA Standards Publication 250.        NEMA defines standards for many commonplace electrical interconnects, as well as outlining manufacturing standards for electrical products, such as various grades of electrical enclosures. • Underwriters Laboratories (USA): UL 1004 - Standard for Electric Motors       Underwriters Laboratories Inc. (UL) is a U.S. for-profit, privately owned and operated product safety testing and certification organization. Based in Northbrook, Illinois, UL develops standards and test procedures for products, materials, components, assemblies, tools and equipment, chiefly dealing with product safety. UL also evaluates and certifies the efficiency of a company’s business processes through its management system registration programs. Additionally, UL analyzes drinking and other clean water samples through its drinking water laboratory in South Bend, Indiana.       UL is one of several companies approved for such testing by the U.S. federal agency OSHA. OSHA maintains a list of approved testing laboratories, known as Nationally Recognized Testing Laboratories.       An unambiguous understanding of your requirements will greatly help you choose what kind of motor is best for the situation. Consider the following factors when choosing motors: 1. Thoroughly understand the power requirements including all auxiliary devices and systems. Motors should not be run beyond their rated load, as they will burn out. 2. Motors generate a lot of heat, so be sure to provide adequate cooling mechanisms. 3. Providing a clean and dry area for the motor prevents breakdowns and also saves lives. 4. Make sure if there be one of the design and manufacturing standards mark. 5. Motor components like brushes, commentators, windings, etc. wear out over a period of time. This leads to reduced output and life expectancy. Motors have to be shut down at the first sign something is malfunctioning.