Snmek 1

Anglicky v odbornch pedmtech"Support of teaching technical subjects in EnglishTutorial: Mechanic - electrician

Topic: Electric measurementthe 2nd. yearMeasuring devices 3Prepared by: Ing. Ji Smlek

Projekt Anglicky v odbornch pedmtech, CZ.1.07/1.3.09/04.0002je spolufinancovn Evropskm socilnm fondem a sttnm rozpotem esk republiky.

Measuring instruments - basic properties of measuring instrumentsMeasuring range: Measuring range reflects the range of values within which the instrument measures with the required accuracyUsually the measuring range coincides with a full scale, Instrument sensitivity :The sensitivity of the device indicates how the deflection of the hands responds to the unit of the measured values.

Constant device foris the reciprocal of sensitivity; expresses the size of the measured variables at one scale interval.formula

unit V/div, A/div, V . A/div

Slovnk:Mc pstroj mic soustava fyzikln podstata kroutic moment rukaselnkstupnicedc pruiny -direktivn (dc) momenttlumenMc souprava mc pstrojemstkypomocn zazen

Frazeologie:Mc pstroj se skld : mic soustava - fyzikln podstata pemny veliiny na kroutic moment rukaselnky se stupnicemidc pruiny - direktivn (dc) momenttlumenMc souprava se skld:mc pstrojemstkypomocn zazen

2Measuring instruments - basic properties of measuring instrumentsChanging the measuring range:DCAmpere meter shaftVoltmetr ballastAC - alsoAmpere meter measuring transformer current - MTPVoltmeter-measuring transformer voltage-MTNCalculation of constants: Shunt, ballast - n times increases the range kP = n kMTP - transfer of the transformer p= I/5AConversion constant transformerKT =p kA MTN - transfer of the transformer p= U/100VConversion constant transformerKT =p kVW meterk= range U x range I / number of scale intervals

Slovnk:Ampr metrbonkVoltmetrpedadnkFrazeologie:Zmna mcho rozsahu : DCAC - takAmpr metr mc transformtor proudu MTPVoltmetr mc transformtor napt- MTNVpoet konstanty : Bonk, pedadnk n krt zvtuje rozsahpevod trafa Pevodn konstanta transformtorupoet dlk stupnice3Measuring instruments - basic properties of measuring instrumentsAccuracy of measuring instruments: expresses the class of accuracy.according to standard: 0,05, 0,1, 0,2, 0,5, 1, 1,5, 2,5 a 5. These numbers indicate the measured values of variables leaving the maximum deviation from the actual size, in% of measuring rangeTo measure accurately, the deflection of the hands must be measured in the last third of the scale.

formula

OverloadOverload means the multiples of the rated current or voltage, that the measuring instrument will last for a period of time without damagevoltmeters doubled,ammeters tenfold,

Slovnk:Petitelnost Pesnost men micch pstroj :

Frazeologie:vyjaduje se tdou pesnosti.podle normy SN :Tato sla udvaj u namen hodnoty veliiny dovolenou maximln odchylku od skuten velikosti, a to v % micho rozsahuchceme-li mit pesn, e vchylka ruky pi men mus bt v posledn tetin stupnice.Petitelnost rozumme nsobek jmenovitho proudu nebo napt, kter mic pstroj vydr po uritou dobu bez pokozenvoltmetry dvojnsobn,amprmetry desetinsobn,

4Measuring instruments - basic properties of measuring instrumentsPower consumption devices: Power necessary to achieve full deflection of the hands

OverloadOverload means the multiples of the rated current or voltage, that the measuring instrument will last for a period of time without damagevoltmeters doubled,ammeters tenfold,Rapid stabilization of displacement of the hands: Reading measurement values - after stabilization of the position of the hands -> longer measurement time.Prevention - damping oscillation rotation of the system.

Slovnk:Frazeologie:Vlastn spoteba pstroj : Vkon potebn k dosaen pln vchylky ruky PetitelnostPetitelnost rozumme nsobek jmenovitho proudu nebo napt, kter mic pstroj vydr po uritou dobu bez pokozenvoltmetry dvojnsobn,amprmetry desetinsobn,Rychlost ustlen vchylky ruky : ten namen hodnoty - a po ustlen polohy ruky > del doba men.Zabrnn - tlumenm kvn oton sti stroj5Measuring instruments - basic properties of measuring instrumentsErrors of measuring instruments: influencing variables, which can alter the measurement data. They are for example:ambient temperature, strange magnetic fields, position of the device, frequency, wave alternating current, influence of ferromagnetic barReference conditions are the sum of the reference values given by the instrument manufacturer for each influence quantity,The reproducibility of measurementsEach correct measurement must be reproducible. This means that repetition with a certain measurement by the same device under the same conditions we get the same results.

Slovnk:Frazeologie:Chyby micch pstroj : ovlivujc veliiny, kter mohou pozmnit mic daj. Jsou to nap.:teplota okol, ciz magnetick pole, poloha pstroje, kmitoet, tvar vlny stdavho proudu, vliv feromagnetickho paneluVztan podmnky jsou souhrn vztanch hodnot udanch vrobcem pstroje pro kadou ovlivujc veliinu,Reprodukovatelnost menKad sprvn men mus bt reprodukovateln. To znamen, e pi opakovn uritho men stejnmi pstroji a za stejnch podmnek musme dostat stejn vsledky.

6Describe what is a measuring range Write how the measuring range is related to the scale Describe what is the instrument sensitivity Write a formulaDescribe what is a constant unit Write a formula

Activities for studentsquestions

Slovnk: Frazeologie:Popi co to je mc rozsahNapi jak m mc rozsah vztah k rozsahu stupnicePopi co to je citlivost pstroje napi vzorecPopi co to je konstanta pstroje7Write how to express accuracy of the meter Name the class of accuracy according to the standard Describe what we have to watch to gauge accuracy (as far as possible)

Activities for studentsquestions

Slovnk: Frazeologie:Napi jak se vyjaduje pesnost mcho pstroje Vyjmenuj tdy pesnosti dle normy Popi co musme sledovat, abychom mili pesn (co nejpesnji)8Write what is meant by overload (thus how we state it)

Name some variables affecting the measurement accuracy Describe what we must do, in order for us to repeat measurements to achieve the same conditions

Activities for studentsquestions

Slovnk: Frazeologie:Napi co rozumme petitelnost (m ji udvme)Vyjmenuj nkter veliiny ovlivujc pesnost menPopi co musme provst, abychom pi opakovanm men doshli stejnch podmnek 9Muk, J. Management ve vzdlvn dosplch. Praha: EUROLEX BOHEMIA, 2000. ISBN 80-7361-269-7.Operan program Vzdlvn pro konkurenceschopnost, ESF 2007 2013.Dostupn na: http://www.msmt.cz/eu/provadeci-dokument-k-op-vzdelavani-pro-konkurenceschopnostUebnice Elektrick men Ing. Pavel Vylegala, SE Ostrava, 2006Uebnice Elektrick men SNTL, 1981Elektrotechnika - Laboratorn cvien pro bakalsk studium - Doc. Ing. Milo Hammer, CSc.

Bibliography