ME 360 Lab 3: Electrical Filters. Joe Schmoe. Lab partners: Sally Smith and John Doe

Transcription

1 ME Lab Repor 3 ME 360 Lab 3: Elecrical Filers Joe Schmoe Lab parners: Sally Smih an John Doe February 30, 004

2 ME Lab Repor 3 Objecive The objecive secion is inene o ell he reaer wha he repor is abou, bu o no use suen-oriene erms an phrases. Normally he objecive will involve conucing experimens an comparing he resuls o heory. This secion shoul be wo or hree senences long. Backgroun The firs purpose of he Backgroun secion is o ell he reaer why he maerial conaine in he repor is imporan o mechanical engineers. Typically, several references will be cie in his secion. Look in your exbooks an on he Inerne for relevan maerials. This porion of he Backgroun will be abou one o wo pages long. The secon par of he Backgroun secion presens he heoreical equaions ha will be use in he repor. Each equaion shoul be erive or reference o a source. No all equaions shoul be erive or reference. Common equaions, such as Newon s 3 r law (Fma), can be simply use wihou erivaion or referencing. The basic rule o follow is ha if you learne he equaion in ME 360, hen i nees o be erive or reference. Frequenly you will nee o inclue circui schemaics, rawings, or phoos in he Backgroun secion o provie aequae explanaion. A few examples of how o work equaions an relevan figures ino your ex are shown in he following paragraphs. Noe ha he equaions are numbere consecuively an he equaion number is flush along he righ han margin. The maerial shown below conains some examples of ways o reference echnical maerial in backgroun secion, accoring o he AA (American sychological Associaion) syle guies. A hypoheical average normal observer, as efine by he Inernaional Commission on Illuminaion in 93, is use o efine he color of ligh. This sanar hypoheical observer is require, because ifferen ses of eyes perceive color ifferenly. The chromaiciy of a color, expresse in erms

3 ME Lab Repor 3 3 of his sanar observer, is given by he numbers x, y, z (calle richromaic coefficiens or rilinear coorinaes), which may be consiere as roughly expressing he respecive re, green, an blue conens of he color. Since he sum of x, y, an z always equals one, he chromaiciy is aequaely specifie by giving only x an y (ITE, Chaper, 998). Ligh inensiy requiremens for raffic signals an highway/railway grae crossing signals have been sae in erms of viewing isance an luminous inensiy a various viewing angles. In 966, he American Associaion of Railroas (AAR) specifie ha crossing signals be clearly visible o a normal viewer in brigh sunligh coniions. Viewing isance, no luminous inensiy, was he crierion by which he signal was measure. Wih a 30-5 lens, he specificaion calle for a range of,500 fee from onaxis o 0 lef an righ (Green & Milanovic, 00). In 999, he American Railway Engineering an Mainenance-of-Way Associaion (AREMA) became responsible for seing sanars. Visibiliy requiremens were given in isance, an he same sanar applie o boh LED an incanescen signals. The viewing isance requiremens were he same as he 966 AAR sanar for he 30-5 lens. However, he 999 AREMA sanar also specifie a beam paern in erms of percenage of on-axis luminous inensiy. The beam paern for an incanescen signal wih a 30-5 lens is shown in Table (Green & Milanovic, 00). Noe he absence of verical lines in an AA syle able. Table ercenage of On-Axis Luminous Inensiy for 30-5 Lens ercenage of On-Axis Horizonal Axis Luminous Inensiy 0 L/R 5 L/R 0 L/R 5 L/R Verical Axis 0 D 00% 63% 3% 3% 5 D % 0 D % 5 D %

4 ME Lab Repor 3 4 Examples of formaing an referencing heoreical equaions are given in his paragraph. The hoop sress,, in a hin-walle cyliner is foun by Equaion from opov (968), () where is he inerior pressure, is he cyliner iameer, an is he wall hickness. If each erm on he righ conribues o he overall uncerainy in sress, hen he formula for uncerainy is given by Equaion (Wheeler & Ganji, 996) as + + U U U U. () Since he equaion for sress is a simple polynomial in each of he hree variables, he parial erivaives are foun o be,,. (3) Diviing each erm by he equaion for sress gives, (4), (5). (6) Diviing each erm in Eqn. by he sress, s, an subsiuing Eqn. 4, 5, an 6 gives he simplifie version of he uncerainy formula for sress

5 ME Lab Repor 3 5 U U U + U +. (7) Experimen The proceure ha you use o conuc he lab experimen is escribe in his secion. Since his happene previously he pas ense is normally use in he Experimen secion of a lab repor. Iems ha shoul be specifically inclue are escripion of he experimenal seup, incluing he imensions of beams, weighs of masses, componen values in op-amp circuis, ec. Annoae phoographs, iagrams, skeches, or schemaics showing he basic seup an all relevan imensions an/or componen values are also require. Descripions of all es equipmen use shoul be inclue, especially he name of he manufacurer an he moel number. The maerial ha follows is inene o show formaing an shoul no be use as an exac guie o conen. Tesing of crossing signals an waysie signals requires ha measuremens of ligh inensiy an chromaiciy be aken a various angles likely o be encounere by rain crews an rivers. The ITE specificaion has 44 require es poins, ranging from 7.5 lef an righ of he verical axis, an from.5 o 7.5 own from he horizonal axis, as shown in Figure. This paern was use in all of he experimens conuce for his repor Verical Angles Horizonal Angles -7.5 Figure. ITE-syle es angles

6 ME Lab Repor 3 6 The goniomeer esigne an buil for his research is shown in Figure. A Vexa Sepper Moor moel K566NAWA an a 30: Tsubakimoo Emerson gearbox, moel TM0E, are bole o he mile of he base plae. This sepper moor conrols he movemen abou he verical axis of he goniomeer. The power supply an rivers for he sepper moors are also locae on he base plae. Horizonal Axis Sepper Moor an 30:Gearbox illow Block Bearings Sepper Moor ower Supply 30: Gearbox Sepper Moor Driver Figure. Goniomeer. A Naional Insrumens CI-7344 moion conrol boar was use o conrol he sepper moors. The power supply is a Nemic Lamba moel HR-0-4, which can provie an oupu curren of 3 amps a 4 vols o he sepper moors. A Minola Chroma Meer, moel CS-00A, was use for all luminous inensiy an chromaiciy measuremens. This colorimeer has a one-egree accepance

7 ME Lab Repor 3 7 angle, which allows accurae measuremen of he safey signal wihou incluing ambien ligh from he es area. The LED signals were powere by a Hewle-ackar 6038A power supply. Tess on he LED signals were run by placing he signal in he goniomeer, aligning he signal wih he colorimeer, hen running he LabView esing program. The signals were aligne wih he colorimeer prior o esing. The colorimeer is place approximaely 57.3 fee away from he signal. As shown in Figure 3, his allows he one-egree accepance angle of he colorimeer o measure he enire -inch iameer signal. The colorimeer is posiione on he ripo such ha he enire signal is insie he viewing circle. Horizonal roaion axis in egree Top View Minola CS-00A Colorimeer in egree Verical roaion axis 57.3 fee Sie View Figure 3. Layou of es seup for inch signals. Resuls In his secion of he repor is he concise presenaion of he significan resuls of he effor in wors, ables, an figures. Typically, his will inclue a comparison of experimenal resuls o heory. An

8 ME Lab Repor 3 8 uncerainy analysis an an evaluaion of is resuls is also ypically inclue. If here is no a close mach beween he experimenal an heoreical resuls, a analysis of sources of error in he experimenal echnique shoul be inclue. Any quesions specifically aske in he lab hanou mus be aresse. All ables an figures shown in he Resuls secion mus be iscusse in he ex. Deaile ables of raw aa, liss of assumpions, an sample calculaions are inclue in he Appenix, bu shoul be menione in he Resuls secion. The maerial inclue in he nex few paragraphs is inene o show an example, an shoul no be inerpree as a comprehensive se of Resuls. Figure 3 shows he resuls of one of a series of ess conuce o eermine he poin source correcion facor for he re WS#7 signal. Figures A hrough A5 of he Appenix show he resuls of aiional ess. Figure 4 summarizes he resuls from his series of ess, which were very inconsisen. Uner ieal circumsances he oupu of his signal shoul have somewha approximae he inverse square law shown in Figure 4. In several cases moving he signal furher from he measuring colorimeer cause he maximum ligh inensiy o increase which shoul no have happene. The exac reason for he erraic behavior of his signal is unknown, bu is mos likely ue o he narrow beam angle (3 egrees) of he WS#7 signal making he iniial alignmen more criical han wih he welve inch crossing signals.

9 ME Lab Repor Ligh Inensiy (canela) Verical Angle (egrees) Horizonal Angle (egrees) 0 Figure 3. Experimenal resuls from WS#7 signal a 38 fee. 800 Maximum Ligh Inensiy, Canela Firs Tes Series Secon Tes Series Theoreical Inverse Square Disance, Fee Figure 4. Maximum ligh inensiy vs. isance for WS#7signal.

10 ME Lab Repor 3 0 Table summarizes he resuls from an aiional se of ess on he WS#7 signal. These ess were conuce o eermine he effec of non-illuminae elemens on he ligh oupu from he signal. As shown in he able, he ligh oupu from he WS#7 signal is no a funcion of he number of acive elemens, wih maximum oupus ranging from 63 o 05 canela. Supply curren an power consumpion are essenially consan a amps an was, respecively. The number of open-circuie elemens has a negligible effec on he power requiremens for he WS#7 signal. The relaive insensiiviy of he WS#7 signal o he number of open-circuie elemens is ue o wo facors:. he use of a power supply o regulae volage an curren, an. he combine series an parallel arrangemen of LEDs (shown in Figure WS7a). There is also a consan relaionship beween he maximum ligh inensiy oupu an he power consumpion of beween 79. an 8.5 canela/wa. Table Resuls from WS#7 a 0.0 vols, Open-Circuis ercenage Number Maximum Supply ower Ligh-ower of LEDs of LEDs Ligh Inensiy Curren Consumpion Efficiency ON ON (canela) (amps) (was) (canela/wa) 95.5% % % % % % Figure 6 shows he chromaiciy resuls from he same ess shown in Table. Uncerainy calculaions are conaine in he Appenix. The uncerainy for each measuremen is represene in Figure 6 by error bars. All of he resuls show very similar color values clusere fairly close o he ege

11 ME Lab Repor 3 of he AREMA limis for re waysie signals. The small ifferences in he mean color values are much less han he ifferences measure uring he es, as shown by he error bars. There is no apparen color shif ue o varying he percenage of ON elemens via open circuiing wih he WS#7 signal "y" value "x" value Figure 7. Chromaiciy of he WS#7 signal wih ifferen combinaions of LEDs illuminae, opencircuie. Conclusions The conclusions of your repor nee o be a shor paragraph ha resaes he major resuls an inerpreaions of hose resuls. A reaer, such as a boss, shoul be able o unersan wha happene in he work ha is repore. A porion of he acual conclusions from he echnical repor on LED (ligh emiing ioe) signals use in railway applicaions is given in he nex paragraph. In general, he ligh inensiy responses (in erms of peak ligh oupu in canela) of LED unis ha o no use power supplies are very sensiive o boh he supply volage an he number of acive

12 ME Lab Repor 3 LED elemens. The LED signals ha use power supplies have, in general, ligh inensiy responses ha are much less sensiive (in many cases insensiive) o power supply variaions an he number of acive LED elemens. The primary conclusion ha can be rawn from hese observaions is ha here is no consisency in he performance of all ypes of LED crossing signals wih respec o power supply variaions or he number of acive LED elemens. References Wheeler, A.J., & Ganji, A.R. (996). Inroucion o engineering experimenaion. Upper Sale River, NJ: renice-hall. Green, D. & Milanovic M. (00). LED echnology for improve conspicuiy of signal lighs a roa/railway grae crossings. Carmanah Technologies, Inc., Vicoria, BC. Insiue of Transporaion Engineers. (998). Chaper : Vehicle Traffic Conrol Signal Heas. Equipmen an Maerial Sanars. Washingon D.C. opov, E.. (968). Inroucion o mechanics of solis. Englewoo Cliffs, NJ: renice-hall.

13 ME Lab Repor 3 3 Appenix Conens. Assumpions for uncerainy values page 3. Sample calculaion for heoreical break frequency page 3 3. Sample calculaion for uncerainy in he heoreical break frequency page 4 4. Sample calculaion for experimenal gain page 4 5. Sample calculaion for uncerainy in experimenal gain page 4 6. Raw aa pages 5-5 Assumpions for uncerainy values Measuremens mae wih Naional Insrumens VirualScope: o Frequency uncerainies are ± % (of reaing) + igi Measuremens mae wih LG recision DM-44B igial mulimeer: o Resisance uncerainies are ± 0.% (of reaing) + igis Measuremens mae wih Daa recision 938 capaciance meer: o Capaciance uncerainies are ± 0.5% (of reaing) + igi Sample calculaion for heoreical break frequency

14 ME Lab Repor 3 4 Sample calculaion for uncerainy in he heoreical break frequency Sample calculaion for experimenal gain Sample calculaion for uncerainy in experimenal gain