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91.
IZDELAVA IN VODENJE VEČNAMENSKEGA TRIOSNEGA CNC STROJA
David Javor, 2012, undergraduate thesis

Abstract: V diplomskem delu smo se ukvarjali z izdelavo in vodenjem večnamenskega CNC stroja. Celoten sistem sestoji iz koračnih motorjev, senzorjev, močnostnega dela in napajalnika. Za praktičen prikaz so uporabljeni trije koračni motorji za XYZ gibanje ter model CNC stroja. Uporabljen protokol za dvosmeren prenos informacij od krmilnega do močnostnega dela je LPT port. Krmilni del predstavlja vmesnik z integriranim vezjem (TB6560HQ), ki ima integriran prožilni del za PWM regulacijo in močnostni del s H-mostičom, ki spreminja smer in jakost toka skozi navitje koračnih motorjev in jim daje dovolj navora za poganjanje osi. Vse procese pa upravlja računalnik oz. programski opremi Mach3 in EMC2, ki sta tudi uporabljeni pri profesionalnih maksimiziranih strojih. Model večnamenskega stroja je skonstruiran s programskima paketoma CoCreate modelling, CoCreate Drafting in sestavljen s pomočjo aluminijastih profilov in trapeznih vreten, saj so cenovno ugodnejša, vendar manj točna od krogelnih vreten.
Keywords: koračni motor, senzorji, krmilna in močnostna enota, programska paketa MACH3 in Ballbar, CNC konstrukcija
Published: 23.05.2012; Views: 3164; Downloads: 688
.pdf Full text (4,80 MB)

92.
VPLIV NAVITJA IN ZRAČNE REŽE NA KARAKTERISTIKE TRIFAZNEGA ASINHRONSKEGA MOTORJA
Rok Ravljen, 2012, undergraduate thesis

Abstract: Diplomsko delo obravnava vpliv navitja in zračne reže na karakteristike trifaznega asinhronskega motorja. Karakteristike asinhronskega motorja smo izboljšali s struženjem rotorskega paketa. S tem smo motorju povečali zračno režo, zmanjšali glave navitja in izboljšali vrtilni moment motorja. Opravili smo meritve različnih obratovalnih stanj. S programskim paketom emLook smo opravili izračun in ga tako primerjali z analitičnim, katerega smo opravili brez pomoči računalnika. Primerjavo smo naredili med asinhronskimi motorji z različnimi karakteristikami in pri tem ugotovili, da ima trifazni asinhronski motor z vstavljenim ulomljenim koncentričnim navitjem največji omahni vrtilni moment. Vso delo v zvezi z diplomsko nalogo je bilo opravljeno v Laboratoriju za električne stroje na Fakulteti za elektrotehniko, računalništvo in informatiko v Mariboru.
Keywords: Asinhronski motor, načrtovanje, meritve, analitični izračun
Published: 17.05.2012; Views: 1657; Downloads: 97
.pdf Full text (3,70 MB)

93.
Dynamic two-axis model of a linear synchronous reluctance motor based on current and position-dependent characteristics of flux linkages
Gorazd Štumberger, Bojan Štumberger, Drago Dolinar, 2006, original scientific article

Abstract: This paper analyses the impact of armature slotting and magnetically nonlinearand anisotropic iron core on the trajectories of a kinematically controlled linear synchronous reluctance motor (LSRM). A new magnetically nonlinear dynamic two-axis LSRM model is introduced in order to perform the analysis. The magnetic nonlinearities and slotting effects are accounted for by the current and position-dependent characteristics of flux linkages.
Keywords: devices motors, reluctance synchronous motor, iron core model
Published: 31.05.2012; Views: 1342; Downloads: 55
URL Link to full text

94.
Modelling and analysis of thermal and stress loads in train disc brakes - braking from 250 km/h to standstill
Marko Reibenschuh, Grega Oder, Franc Čuš, Iztok Potrč, 2009, original scientific article

Abstract: Thermal and stress analysis of disc brakes under specific loads (driving downhill and braking to a standstill) was calculated. The FEM (Finite Element Method) was used to carry out the analysis. The analysis dealt with centrifugal load for two cases of braking, braking to a standstill on a flat surface and braking downhill, maintaining constant speed and afterwards braking to a standstill. The main boundary condition in both cases was the entered heat flux on the braking surface of the disc and the force of the brake clamps. Two different discs were used, one brand new (unused) and one with permitted wearing.
Keywords: discs brake, temperature conditions, temeprature loads, locomotives, motor train set
Published: 31.05.2012; Views: 1054; Downloads: 23
URL Link to full text

95.
LABORATORIJSKA SIMULACIJA POGONA DVIGALA
Jernej Brodej, 2015, undergraduate thesis

Abstract: V diplomskem delu je predstavljena simulacija pogona dvigala pri različnih obremenitvah. Prvi del naloge je razdeljen na zbiranje in analiziranje podatkov o pogonih dvigal. Podrobno so opisana dvigala KONE in njihova energetska učinkovitost. Prikazan je način delovanja napajalnika in pogonskega motorja, ki sta bila uporabljena pri sami simulaciji. V drugem delu naloge pa je podan opis nastavljanja parametrov napajalnika, s katerimi zagotovimo mehak zagon in ustavljanje dvigala.
Keywords: dvigala, električni pogon, asinhronski motor, frekvenčni pretvornik
Published: 28.09.2015; Views: 606; Downloads: 188
.pdf Full text (3,18 MB)

96.
IDENTIFIKACIJA PARAMETROV ENOSMERNEGA MOTORJA ZA NAMENE VODENJA
Enida Suljić, 2015, undergraduate thesis

Abstract: Enosmerni motorji so uporabljeni na različnih področjih in v večini primerov težimo k izvedbi kvalitetne in zanesljive regulacije hitrosti vrtenja, toka oz. navora ali pozicije. Za načrtovanje zaprto-zančnega vodenja ene izmed prej naštetih veličin potrebujemo natančne parametre enosmernega motorja. Parametre motorja je možno določiti preko linearnega ali nelinearnega matematičnega modela, ki dokaj precizno opisuje dinamične lastnosti celotnega vodenega sistema, kar je tudi predmet predlaganega diplomskega dela. V sklopu te diplomske naloge sta uporabljeni dve metodi za pridobitev parametrov. Kot linearni postopek optimizacije je uporabljena metoda identifikacije z metodo najmanjših kvadratov v okvirju orodja Ident Toolbox znotraj Matlaba. Kot nelinearni postopek pa metoda z uporabo funkcije »fmincon« v okvirju optimizacijskega orodja Optimization Tool tudi znotraj Matlaba. Glavni cilj je pridobitev vrednosti neznanih parametrov enosmernega motorja primerjava med obema metodama: uporabnost in primernost obeh, prednosti in slabosti ter natančnost končnih rezultatov.
Keywords: identifikacija, metoda najmanjših kvadratov, fmincon, enosmerni motor, parametri
Published: 27.08.2015; Views: 845; Downloads: 148
.pdf Full text (1,79 MB)

97.
98.
Adjustments differ among low-threshold motor units during intermittent, isometric contractions
Dario Farina, Aleš Holobar, Marco Gazzoni, Damjan Zazula, Roberto Merletti, Roger M. Enoka, 2009, original scientific article

Abstract: We investigated the changes in muscle fiber conduction velocity, recruitment and derecruitment thresholds, and discharge rate of low-threshold motor units during a series of ramp contractions. The aim was to compare the adjustments in motor unit activity relative to the duration that each motor unit was active during the task. Multichannel surface electromyographic (EMG) signals were recorded from the abductor pollicis brevis muscle of eight healthy men during 12-s contractions (n = 25) in which the force increased and decreased linearly from 0 to 10% of the maximum. The maximal force exhibited a modest decline (8.5 +- 9.3%; P < 0.05) at the end of the task. The discharge times of 73 motor units that were active for 16-98% of the time during the first five contractions were identified throughout the task by decomposition of the EMG signals. Action potential conduction velocity decreased during the task by a greater amount for motor units that were initially active for >70% of the time compared with that of less active motor units. Moreover, recruitment and derecruitment thresholds increased for these most active motor units, whereas the thresholds decreased for the less active motor units. Another 18 motor units were recruited at an average of 171 +- 32 s after the beginning of the task. The recruitment and derecruitment thresholds of these units decreased during the task, but muscle fiber conduction velocity did not change. These results indicate that low-threshold motor units exhibit individual adjustments in muscle fiber conduction velocity and motor neuron activation that depended on the relative duration of activity during intermittent contractions.
Keywords: electromyography, surface electromyography, multi-channel EMG, motor units, decompostion, recruitment treshold, derecruitment treshold_
Published: 01.06.2012; Views: 955; Downloads: 58
URL Link to full text

99.
Impact of magnetic saturation on the steady-state operation of the controlled induction motor
Petar Ljušev, Drago Dolinar, Gorazd Štumberger, 2003, original scientific article

Abstract: The paper presents a method for determination of the steady-state torque characteristics of the induction motor in the case of rotor field-oriented control (RFOC) with nonlinear magnetizing characteristic of the iron core included. The torque characteristics are determined for the constant stator current and the constant d-axis stator current. The characteristics obtained at a constant stator current are used to maximize the torque capability of the RFOC induction motor. The aim of the presented work is to obtain required steady-state torque with minimal stator current. Experiments show that the proposed selection of a magnetizing reference is promising.
Keywords: induction motor, torque characteristics, magentic saturation
Published: 01.06.2012; Views: 843; Downloads: 11
URL Link to full text

100.
PROIZVODNJA ELEKTRIČNE ENERGIJE Z ZEMELJSKIM PLINOM
Mitja Slatinjek, 2015, undergraduate thesis

Abstract: Naloga temelji na enem izmed procesov pretvarjanja zemeljskega plina v električno in toplotno energijo. V začetku bo predstavljeno delovanje Stirlingovega motorja in Otto motorja. Sledila bo predstavitev kogeneracije, ki bo zajemala opis delovanja sistema in pregled sestavnih delov celotne enote, ki je potrebna za želeno proizvodnjo energije. Narejen bo predračun za kogeneracijo moči 190 kW, prav tako bodo navedeni osnovni tehnični podatki kogeneracij dveh različnih moči, s pomočjo katerih bomo prikazali letni preračun porabe plina ter proizvoda električne in toplotne energije.
Keywords: kogeneracija, Stirlingov motor, Otto motor, zemeljski plin
Published: 04.11.2015; Views: 1394; Downloads: 188
.pdf Full text (2,48 MB)

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