Mass per unit volume of a substance is called density of the body. Units of derived quantities are called derived units. It must be as accurate as possible and should be based on all available engineering and design data. The weight of body changes with acceleration due to gravity. Comparing quantities class 8 notes maths chapter 8 learn cbse. Siebers virginia commonwealth university richmond, virginia usa 2009 aapm summer school. A ratio is a comparison of two quantities by division. Units of measurement physics class 11 download notes in pdf. In this case a standard wall height of 10 per story can be assumed. Per unit pu quantitiesadvantage of per unitrepresentation, one line diagram 2. The per unit system is based on the formula shown in equation 1. How to estimate the cost of interior building finishes from. When maxwell first introduced the concept of a coherent system, he identified three quantities that could be used as base units. In many respects the method is similar to the use of percentage values.
Pdf quantities, units and symbols in physical chemistry. These have a lot of importance as per unit quantities of parameters tend to have similar values even when the system voltage and rating change drastically. The per unit system is a method of expressing quantities in an electrical system e. Per unit system explaination with solved example free download as. Planners should use this in their initial analysis for forecasting proper requirements and adjust requirements as the oper. Massachusetts institute of technology mit opencourseware. Basic radiation interactions, definition of dosimetric quantities, and data sources j. Per unit quantities transformer electronics scribd. Now, we note that there will be base quantities for voltage, current and frequency for each of.
More importantly, while c looks like it is making a loss under traditional costing, abs tells a different story. Per unit quantities, like percentage quantities, are actually fractional quantities of a reference quantity. Jan 15, 2015 the computation effort in power system is very much reduced with thee use of per unit quantities. Per unit notation in per unit notation, the physical quantity isin per unit notation, the physical quantity is expressed as a fraction of the reference vava ue. In the power systems analysis field of electrical engineering, a perunit system is the expression of system quantities as fractions of a defined base unit quantity. The manual is in line with cost estimation system for pbc 2015 hereinafter referred to as costes for pbc 2015, the computer tool used for actual cost estimation exercises.
When quantity shipped to a single destination is less than. Basic radiation interactions, definition of dosimetric. Selina concise physics class 7 icse solutions physical. Two quantities can also be compared using percentages.
This video discusses basics of perunit quantities and is the first in a series of videos on the subject. By definition, the per unit value of a quantity is the ratio of the original quantity to its base value which results in a dimensionless per unit or pu value. Unit of time second the second is the duration of 9 192 631 770 pe. Logistics forecasting estimates brigade combat team. The per unit system permits multiplication and division in addition to addition. They feed supply to 2 motors of inputs 8 mva and 12 mva respectively. Calculation per piece of completely performed item. One can also make a physical quantity with a combination of derived quantities. The perunit impedance of a transformer in a threephase system is the same. Like meals, bulk water planning is calculated on a per person, per day cycle. A power flow study loadflow study is a steadystate analysis whose target is to determine the voltages, currents, and real and reactive power flows in a system under a given load conditions.
Page iv wsdot cost estimating manual for projects m 3034. Jul 04, 2015 this video discusses basics of per unit quantities and is the first in a series of videos on the subject. Per unit system practice problem solved for easy understanding. Other engineering quantities need a little more thought when writing out the basic mlt dimensions. Qup abbreviation stands for quantity per unit pack.
Calculations are simplified because quantities expressed as per unit do not change when they are referred from one side of a. The bills also provide a measure of the extent of work and this allows the work to be priced. Per unit quantities simply theoretical deduction and give them more generalizes forms. Vin per unit vin kvv base in kv where the base value is a reference value for magnitude. When there are large spaces or several similar spaces, the labor productivity for installation increases and the amount of material waste decreases.
All p and q quantities are three phase voltage magnitudes are. Lets understand the concept of per unit system by solving an example. Because of an upcoming modernization of the electric system in unit 3 and 4 at. Usually, the per unit quantities being of the order of unity or less can easily be handled with a digital computer. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Determining quantities per intermediate container quantity icq. Any quantity is converted into per unit quantity by dividing the numeral value by the chosen base value of the same dimension. Ee 423 fault analysis notes university of moratuwa. You can display load consumption quantities and normalized quantities in the item details of a freight unit, transportation unit that is, trailer unit, container unit, or package unit, or freight order. In this derivation, per unit quantities will usually be designated by lower case letters.
Certain physical quantities have been chosen as fundamental or base quantities. The main idea of a per unit system is to absorb large differences in absolute values into base relationships. Singlephase per unit system advantages of the per unit system. All costs are summed to obtain the total estimated construction cost. When two quantities have the same unit of measure, their ratio has no unit of measure. Perunit system for singlephase transfomers the voltages, currents, powers, impedances, and other electrical quantities are measured as fractions of some base level instead of conventional units. The per unit value of any quantity is defined as the ratio of actual value in any unit to the base or reference value in the same unit. Notes for an introductory course on electrical machines and. Accepted purchase order quantities per purchase order and item send feedback. By percentage, we mean a fraction where the denominator is 100. Equipment impedances can be easily estimated since their per unit impedances lie within a relatively narrow range. A unit rate is a rate that is simplified so that it has a denominator of 1 unit. Power flow studies university of nevada, las vegas. Var ind sbase 0similarly as in handling the per unit values of ohmic quantities, both real power andreactive power are compared to the apparent base power, usually called base mva.
Physical quantities, measurements standard and units gk physical quantities, measurements standard and units general knowledge general science gs for upsc, ias, banking, railway ssc and other competitive examinations. Notes for an introductory course on electrical machines. Electric power systems pennsylvania state university. Per unit analysis per unit system power system analysis. Buildcost continuously challenge the design, programme, scope and budgets. Physics is a quantitative science, based on measurement of physical quantities. A rate is a special type of ratio comparing two quantities with different units. It will be easier in the work ahead if we revert to the inverse indice notation and write it as ml3. Therefore, the speakers are placed into inventory until they are needed for assembly into television. Payment for such excavation is generally at the unit contract price per cubic yard. Unit of mass kilogram the kilogram is the unit of mass. Per unit calculation per unit system examples electrical. Aug 02, 2018 prebook pen drive and g drive at teacademy.
Construction contingency a standardized markup applied to the construction cost of a project that accounts for uncertainties in quantities, unit costs, and minor risk events that typically take place during construction. The per unit system overview page 1 of 6 overview the per unit system is based on the formula shown in equation 1. What is the abbreviation for quantity per unit pack. The unit cost for c is 7% lower under abc when compared to traditional costing. The following calculators compute various base and per unit quantities commonly used in the per unit system of analysis by power system engineers.
Units and conversion factors table of contents section page references 3 i. Chapter 8 per unit representation sometimes it is more convenient to. This experience suggested there might be other people much like myselfoutside the power industry, but vitally concerned with it. Description uom quantity unit price total 0100 demolition and dismantling 0101 dismantling of metal doors, windows and partitions, including their removal outside the building and their stacking at a place designated by the investor. A drywall drop soffit is a much higher unit cost than a typical. Shopping centre anchor unit 900 1,100 per m2 shopping centre shop unit 1,100 1,400 per m2 shopping centre covered mall 1,900 3,000 per m2 buildcost act as our client representative on the refurbishment and fit out of our new head offices. To find the units of work done per man in an 8hour day, divide 8 by the manhours per unit. Calculating food costs, selling prices and making a profit 49 unit 18. Thank you for showing interest in buying our book technical calculation and estimators manhours manual you can buy the electronic v ersion of the manual containing all the figurest and other relat ed data at the following prices. Calculations are simplified because quantities expressed as perunit do not. To find the units done by a crew in an 8hour day, multiply the units per man per. Description of units mechanical, electric, magnetic 4 iii. The purpose of power flow studies is to plan ahead and account for various hypothetical situations. Define four quantities in per unit of their respective base values.
Conversion of per unit quantities to volts, ohms, or amperes requires a knowledge of the base that the per unit quantities were referenced to. I invite you to solve the sample problem at the end of video and leave your answers in the. Large quantities the general rule of thumb that there are cost savings for larger volume applies to interior finishes. Per unit quantities example consider a single phase generating unit rated 50,000 kva at 11,000 volts having an inductive reactance of 0. Per unit system explaination with solved example electrical. Things in which quantity is measured are known as units. The purpose of the single line diagram is to supply in concise form of the significant information about the system. The numerator of the fraction is called rate per cent. The computation effort in power system is very much reduced with thee use of per unit quantities.
The per unit system is used in power flow, short circuit evaluation, motor starting studies etc. Chapter 6 ratio and proportion huntington union free. The unit price is then multiplied by the required quantity to find the cost for the work item. View notes eng224 lecture 10 per unit system from eng 224 at charles darwin. Atkinson december 2000 nature of bills bills of quantities comprise a list of items of work which are briefly described. A per unit phase quantity has the same numerical value as the corresponding per unit line.
Figure 3 on page 31 highlights planning factors for this method that are based on the climate. Dimensions and units for physical quantities mksq system 6,7 a. A rate, like a ratio, is a comparison of two quantities, but the quantities may have different units of measuresand their ratio has a unit of measure. Speed v meter per second ms m s 1 ms pressure p pascal pa force per unit area kg m 1 s 2 energy e joule j kg m2 s 2 power w watt w energy per unit time kg m2 s 3 a physical quantity can be expressed with a unique combination of 7 base quantities.
The perunit system was developed to make manual analysis of power systems easier. This video discusses basics of perunit quantities and is the first in a series of videos on the. When making multiple portions of food and using ingredients in many different quantities, it is important to be able to calculate ingredient costs accurately. The work included in the item is defined in detail by the rules in the method of measurement. Physical quantities and units university of florida. Units of measurement physics class 11 download in pdf measurement of physical quantities. The icru has continued to recommend new quantities and units as the need arose, forexample, absorbed dose 1950. Accuracy and completeness are critical factors in all cost estimates. Further, you can view the aggregated values of these quantities in the header data of these documents. The per unit value of any quantity is defined as the ratio of the actual value of the any quantity to the base value of the same quantity as a decimal. Rather determined per unit values serve to assist in the calculation of other system values. Per unit pu quantities the numerical per unit value of any quantity is defined as the ratio of its actual value to another arbitrarily chosen value of quantity of the same dimensions, assumed as the base or reference. When analyzing a real system, all parameters such as voltage, current, power, and impedance can be converted to per unit.
A phasor quantity or phasor, provides information about not only the magnitude. Eng224 lecture 10 per unit system per unit quantities. Transformers can be replaced by their equivalent series impedances. Introduction to per unit calculations pages 1 11 text. Accepted purchase order quantities per purchase order. For a given quantity voltage, current, power, impedance, torque, etc. Bill of quantities civil and specialists works for. The quantity of excavation to be paid for is measured as outlined in section 209.
The determination of per unit values is not the end objective of a study. Unit of length meter the meter is the length of the path travelled by light in vacuum during a time interval of 1299 792 458 of a second. Dimensions of esu and emu electric and magnetic quantities 5 v. For example, if a plane flies 1,920 kilometers in 3 hours, its rate of speed is a ratio that compares the distance traveled to the time that the plane was in. Per unit system for singlephase transfomers the voltages, currents, powers, impedances, and other electrical quantities are measured as fractions of some base level instead of conventional units. Oct 28, 2017 physical quantities, measurements standard and units gk physical quantities, measurements standard and units general knowledge general science gs for upsc, ias, banking, railway ssc and other competitive examinations. In our system the units would be masslength3 or ml3. Measuring inventory performance common metrics for inventory. Chapter 12 quantities, costs, and specifications 12. How to estimate the cost of interior building finishes. However, if the two quantities are not in the same unit, then we convert them into the same unit before comparison.1535 918 180 779 993 1233 792 1170 1470 591 283 689 62 932 526 967 1367 397 1290 848 147 740 873 1581 727 1565 307 210 1160 184 554 9 376 290 1358 1356 862 853 697