Introduction to Electrical Engineering Week 5.1 PDF

University of Science and Technology of Southern Philippines (USTP) & Institute of Integrated Electrical Engineers of the Philippines, Inc.  Lubricants are identified according to types of equipment.  Tool...

University of Science and Technology of Southern Philippines (USTP) & Institute of Integrated Electrical Engineers of the Philippines, Inc.  Lubricants are identified according to types of equipment.  Tools and equipment are lubricated according to preventive maintenance schedule or manufacturer’s specifications.  Measuring instruments are checked and calibrated in accordance with manufacturer’s instructions.  Tools are cleaned and lubricated according to standard procedures.  Defective equipment and tools are inspected and replaced according to manufacturer’s specification.  Work place is cleaned and kept in safe state in line with OSHC regulations. Lubricant  a substance, usually organic, introduced to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move  It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. Functions of Lubrication:  To lubricate each part of the bearing, and to reduce friction and wear.  To carry away heat generated inside bearing due to friction and other causes.  To cover rolling contact surface with the proper oil film in order to prolong bearing fatigue life. Oils  thin liquids made of long polymer chains, with additives for various extra properties  Common additives include antioxidants to keep the oil from oxidizing, corrosion inhibitors to prevent parts from corroding, and detergents to keep deposits from forming.  These long chains are hard to squeeze out from between surfaces, making oils useful as a slippery barrier between them.  Oils come in different “weights” (such as 5W or 10W), which correspond to viscosity.  The lower the number, the thinner the oil, and the more easily it will flow. Uses: Hinges, bearings, tool maintenance, sharpening blades Types: Motor oil, 3-in-1 oil, sewing machine oil, bar and chain oil Use When: You want to lubricate something without the resistance inherent in using grease You need lubrication to wick into a small space, without having to take anything apart Don’t Use When: The surfaces being lubricated are exposed to dust or dirt, which can eventually gum up and cause more friction You need to keep things around the surfaces clean, because oils are low in viscosity and thus tend to drip and run The surfaces are exposed to water or anything that can wash the oil away. It won’t last long! (While oil can help make things water resistant, it can also absorb water over time. The more water that absorbs into the oil, the lower its adhesion will be, causing it to wash off of the very parts that need lubrication.) Greases  It is made by using oil (typically mineral oil) and mixing it with thickeners (such as lithium-based soaps).  They may also contain additional lubricating particles, such as graphite, molybdenum disulfide, or polytetrafluoroethylene (PTFE, aka teflon).  It combine the lubricating properties of oils with added stickiness, allowing the lubricant to adhere to the surfaces better.  It can even act as a barrier, protecting the surfaces from contaminants that can corrode or damage them.  Like oils, greases come in a range of consistencies, from ketchup-thin to thick like cheddar cheese.  One downside to grease is that because it’s so thick and sticky, it can cause resistance in small or fast-moving mechanisms. Uses: Gears, bearings, chains, linkages Types: White lithium grease, marine grease, silicone grease  Heavy-duty grease Red ‘n’ Tacky grease Marine grease Use When: You need lubrication to stay put and stick to surfaces for a long time You want to seal out contaminants such as water or dust You use a machine so infrequently that you may forget to oil it Don’t Use When: You have fine or fast-moving mechanisms where thick grease would create too much resistance You don’t want a mess. When parts move, they can fling grease all around, so it may not be the best option for keeping things clean Penetrating Lubricants  the saviors of many stuck-bolt combatants, loosening years of rust and debris in minutes.  Contrary to the other substances covered here, penetrating oils are not designed for long-lasting lubrication.  Instead, they are low-viscosity oils with additives that are specifically designed for one purpose: o to infiltrate the tiny cracks between surfaces (such as screw threads) o add lubrication o break up rust  In an experiment conducted by Drexel University engineering students: mixture of vegetable oil and acetone works as well (or better) than WD-40 at loosening stuck bolts.  Mix up a solution that’s 90% vegetable oil and 10% acetone, and squirt it wherever necessary.  Be careful when mixing, as acetone is flammable, and will melt many plastic containers.  If possible, use a glass or metal container to mix it, or buy an oil can to make things even easier.  Shake the mixture before each use, as acetone and vegetable oil tend to separate over time. Dry Lubricants  SBLubrication_TeflonDryLube-8Dry lubricants are made up of lubricating particles such as graphite, molybdenum disulfide, silicone, or PTFE.  At the molecular level, these particles are super slippery, so they reduce the friction between surfaces in contact with one another.  It’s common to find these lubricants in spray form, where they are mixed with water, alcohol, or some other solvent that will evaporate away after application, leaving behind a thin film. Uses: 3D printer rails, threaded rods, locks, hinges Types: Graphite powder or spray, molybdenum disulfide spray, (dry) silicone spray, PTFE spray SBLubrication_PowderedGraphite-6 Powdered graphite Use When: You have tiny parts that shouldn’t be gunk up by grease or oil that will attract dust You need to keep surrounding surfaces clean Your surfaces are exposed to extremely high heat or pressure, which would typically oxidize oils Don’t Use When: Your surfaces are exposed to solvents or other liquids that can wash them away Types and Uses of Lubricants Anti-rust lubricant spray  loosen rusted part  cleans and protect It can isolate the moisture and air to  drives out moisture avoid metal oxidation.  stops squeaks Scope: Rust prevention  ​free sticky mechanisms Lubricating Cleaning Features: 1. Starts wet motors. 2. Stops squeaks. 3. Lubrication to loosen rusty, frozen and sticky parts. 4. Protection against rust and metal corrosion. Wire Pulling Lubricant  does not damage insulation  cling to wire and dries to a slippery film  suitable for use with wire or cable covered with rubber (T, THW, THHN, etc.) Wire-pulling compound  cable lube or lubricant  designed to make it easier to pull electrical wires and cables through conduit runs  It comes in a few different forms and reduces the coefficient of friction between wires and conduits to help minimize damage to the wire insulation or cable jackets and make pulling smoother, safer, and faster.  All Purpose Anti Rust Lubricant  anti-rust Formulated to lubricate, penetrate, and displace moisture,  lubricating leaving parts with a protective  rust removal anti-rust film. This lubricant  decontamination protects metal parts which helps eliminate pounding and breakage  conductance during disassembly. It is easy to spray, has good Features and Benefits: flow, excellent penetrating  Penetrates hard to reach places on contact power and forms a thin  Frees and lubricates frozen and rusted protective film on the metal parts surfaces of machines,  Displaces moisture industrial equipment and  Inhibits rust and corrosion and protects metal surfaces parts that prevents corrosion  Cleans and degreases tools and due to exposure to moisture, equipment salt or chemicals.  Unique aerosol can spray in any position  Lubricant Oil and Engine Oil  lubricating the gear  cleans and protect  drives out moisture Lubricating oil, sometimes simply called lubricant/lube, is a class of oils used to reduce the friction, heat, and wear between mechanical components that are in contact with each other. Lubricating oil is used in motorized vehicles, where it is known specifically as motor oil and transmission fluid. There are two basic categories of lubricating oil: mineral and synthetic. Mineral oils are lubricating oils refined from naturally occurring crude oil. Currently the most commonly used type because of the low cost of extracting the oils from crude oil. Manufactured to have a varying viscosity, therefore making them useful in a wide range of applications. Synthetic oils are lubricating oils that are manufactured. Silicon Lubricant Silicone grease, sometimes called dielectric grease, is a waterproof grease  heat stable made by combining a silicone oil with a  lubricates thickener. Most commonly, the silicone oil is  protects polydimethylsiloxane (PDMS) and the thickener is amorphous fumed silica. Using  reduces friction this formulation, silicone grease is a  water repellent translucent white viscous paste, with exact properties dependent on the type and proportion of the components. More specialized silicone greases are made from fluorinated silicones or, for low-temperature applications, PDMS containing some phenyl substituents in place of methyl groups. Other thickeners may be used, including stearates and powdered polytetrafluorethylene (PTFE). A good lubricant possesses the following characteristics:  High boiling point  Low freezing point  High viscosity index  Thermal stability  Hydraulic stability  Demulsibility  Corrosion prevention  High resistance to oxidation Solvent  from the Latin solvō, "loosen, untie, solve"  a substance that dissolves a solute, resulting in a solution  a substance that dissolves another substance  a liquid (mostly, however it can be a solid or gas as well) in which another liquid or solid is dissolved.  These are mainly used for preparing solutions for carrying out chemical reactions and for cleaning purposes (in a household). Categories:  Polar Solvent o Large Dipole Moments o solvents which dissolve/are soluble in water  Non-polar Solvent o Small Or Zero Dipole Moment o solvents which do not dissolve/are insoluble in water A solvent is a liquid that serves as the medium for a reaction. Two major purposes: 1. (Non-participatory) to dissolve the reactants. Remember “like dissolves like” ? Polar solvents are best for dissolving polar reactants (such as ions); nonpolar solvents are best for dissolving nonpolar reactants (such as hydrocarbons). 2. Participatory: as a source of acid (proton), base (removing protons), or as a nucleophile (donating a lone pair of electrons). The only class of solvents for which this is something you generally need to worry about are polar protic solvents  Polar solvents have large dipole moments (aka “partial charges”); they contain bonds between atoms with very different electro-negativities, such as oxygen and hydrogen.  Non polar solvents contain bonds between atoms with similar electro-negativities, such as carbon and hydrogen (think hydrocarbons, such as gasoline). Bonds between atoms with similar electro-negativities will lack partial charges; it’s this absence of charge which makes these molecules “non-polar”. Two direct ways of measuring polarity: 1. Measuring a constant called “dielectric constant” or permitivity. The greater the dielectric constant, the greater the polarity (water = high, gasoline = low) 2. Measuring the dipole moment. Polarity is a continuum. Pentane is “non-polar”, and water is “polar”, there are borderline cases like diethyl ether, dichloromethane, and tetrahydrofuran (THF) which have both polar and non-polar characteristics. In a pinch, a good rule-of- thumb dividing line between “polar” and “non-polar” is miscibility with water. Diethyl ether and dichloromethane don’t mix with water; THF, DMSO, acetonitrile, DMF, acetone and short-chain alcohols do. Types of Solvents: The chemical classification of a solvent is based on its chemical structure.  Hydrocarbon solvents  classified into three sub-groups based on the type of “carbon skeleton” of their molecules, giving us the aliphatic, aromatic and paraffinic solvents families. Paint thinner is a common example of a hydrocarbon solvent.  Oxygenated solvents  produced through chemical reactions from olefins (derived from oil or natural gas), giving us the following sub-groups: alcohols, ketones, esters, ethers, glycol ethers and glycol ether esters. The human body naturally produces ketones when it burns fat.  Halogenated solvents  solvents that contain a halogen such as chlorine, bromine or iodine. Many people recognize perchloroethylene as an example – a highly effective solvent used in dry cleaning. Commonly used solvents:  Trichloroethylene (TCE)  for dry-cleaning applications.  Chloroform  excellent solvent, however its use is limited to research and industrial application.  Ethanol  used to dissolve a number of chemicals, used extensively in research work and in perfumes.  Toluene  used in paint thinners.  Acetone  nail polish cleaner. Cleaning Solvents Solubility in Polar Nonpolar Uses water Water Soluble X Wash dust in the floor, walls, etc. Gasoline Insoluble X Wash greasy tools/equipment Kerosene Insoluble X Remove dust, grease oil, paint, etc. Thinner Insoluble X Remove spilled paint on the floor, walls and tools. Detergent soap Soluble X Wash/Clean benches, tables, cabinets, etc.