analiza naprezanja u ucvršcenju polova rotora generatora s ...
analiza naprezanja u ucvršcenju polova rotora generatora s ...
analiza naprezanja u ucvršcenju polova rotora generatora s ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Ma{instvo 2(7), 63 – 74, (2003)<br />
N.[virig;....: ANALIZA NAPREZANJA U U^VR[^ENJU...<br />
S porastom optere}enja (centrifugalne sile na<br />
originalima), treba izbjegavati izradu korijena pola u<br />
obliku lastinog repa i treba se orijentirati na<br />
korijene pola u obliku ~eki}a ili kombinacije lastin<br />
rep-~eki}, kod kojih je faktor koncentracije<br />
<strong>naprezanja</strong> manji i do 40% u odnosu na korijen<br />
oblika lastinog repa.<br />
Korijen pola s tri ~eki}a (model VI) treba se<br />
koristiti u onim slu~ajevima kada su optere}enja na<br />
korijen pola vrlo visoka tj. na korijen pola oblika<br />
jednostrukog ~eki}a izazivala bi <strong>naprezanja</strong> znatno<br />
iznad granica te~enja materijala koji se koriste za<br />
izradu polnih plo~a. Na taj na~in pove}ava se<br />
kriti~ni presjek tri puta pa se i <strong>naprezanja</strong><br />
smanjuju u tom omjeru.<br />
Kod modela VI, faktor koncentracije <strong>naprezanja</strong><br />
znatno se smanjuju (tablica 5.3.), u odnosu na<br />
ostale modele kod kojih je pol bio izra|en u<br />
obliku jednostrukog korijena, te se zato kod<br />
brzohodnih strojeva i velikih optere}enja uvijek<br />
mora i}i na izradu u~vr{}enja korijena pola oblika<br />
vi{estrukih ~eki}a.<br />
Rezultati ispitivanja nisu potpuno egzaktni budu}i je<br />
ispitivanje vr{eno uz aproksimaciju tj. polovi su na<br />
originalnoj konstrukciji optere}eni certifugalnim<br />
silama, dok su modeli bili optere}eni jednolikom<br />
vla~nom silom (ravninski model).<br />
Za daljnja istra`ivanja predvi|a se <strong>analiza</strong><br />
<strong>naprezanja</strong> na prostornom rotacionom modelu<br />
metodom zamrzavanja <strong>naprezanja</strong> uz simulaciju<br />
djelovanja centrifugalnih sila na u~vr{}enje pola<br />
<strong>rotora</strong> kako bi se uvjeti ispitivanju na modelu {to<br />
vi{e pribli`ili stvarnim pogonskim uvjetima.<br />
When the loading increases (centrifugal forces on<br />
the originals), the pole root in the shape of a<br />
swallow’s tail should be avoided. The design of<br />
the pole roots in the shape of a hammer or<br />
combinations of a swallow’s tail-hammer where the<br />
stress concentration factor is smaller than 40%<br />
compared to a swallow’s tail should be given<br />
priority.<br />
The pole root with three hammers (model VI) is<br />
used in the cases when the pole root loadings<br />
are very high, i.e. on a single hammer they would<br />
cause stresses far above the material limits, i.e.<br />
materials used for making pole root plates. In this<br />
way the critical cross section is increased three<br />
times. Consequently, stresses are reduced in that<br />
direction.<br />
With the model VI, stress concentration factor<br />
decreases considerably (Table 5.3.) compared to<br />
other models whose pole was made in the shape<br />
of a single root. Therefore, when fast speed<br />
machines and heavy loading are considered, it is<br />
always important to make poles with multiple<br />
hammers.<br />
Test results are not completely exact since tests<br />
were carried out with approximation, i.e. the poles<br />
on the original construction were loaded by<br />
centrifugal forces, whereas models were loaded by<br />
a uniform tensile strength (plane model).<br />
Further research should include the stress analysis<br />
on a rotary model using the freezing stress<br />
method along with centrifugal forces simulation on<br />
rotor poles fixing. In that, the way testing<br />
conditions on the model would be as close as<br />
possible to the real driving conditions.<br />
7. LITERATURA - REFERENCES:<br />
[1] I. Alfirevi}, S. Jeci}, Fotoelasticimetrija,<br />
Sveu~ili{na naklada Liber, Zagreb, 1983.<br />
[2] M.M. Filonenko-Borodi}, Teorija uprugosti,<br />
Gostehizdat, Moskva-Lenjingrad, 1947.<br />
[3] M.M. Frocht, Photoelasticity, I i II, John Wiley<br />
and Sons, New York, 1948.<br />
[4] V. Jari}, Naprezanja u elementima u~vr{~enja<br />
<strong>generatora</strong> s istaknutim polovima (lastin rep),<br />
Elaborat TG 66.0000, Tvornica <strong>generatora</strong> –<br />
''Rade Kon~ar'', Zagreb, 1978<br />
[5] V. Jari}, D. Pustaji}, B. Mila{in~i}, Mehani~ki<br />
prora~un <strong>generatora</strong> s istaknutim polovima,<br />
Tvornica <strong>generatora</strong> – ''Rade Kon~ar'', Zagreb,<br />
1979<br />
[6] S. Jeci}, Teorija elasti~nosti, Sveu~ili{na<br />
naknada Liber, Zagreb, 1981.<br />
[7] S.N. Nikiforov, Teorija uprugosti i plasti~nosti,<br />
Gosizdat, Moskva, 1955<br />
[8] D. Pustaji}, Prora~un i dimenzioniranje<br />
u~vr{~enja pola lastinim repom, Elaborat<br />
60.0001, Tvornica <strong>generatora</strong> – ''Rade Kon~ar'',<br />
Zagreb, 1978<br />
[9] D. Pustaji}, N. [vigir, Analiza <strong>naprezanja</strong> u<br />
lastinom repu <strong>generatora</strong> s istaknutim<br />
polovima, Referat na XVII savjetovanju<br />
elektroenergeti~ara Jugoslavije, Struga, 1985,<br />
str.19-29<br />
[10] N. [vigir, Izbor materijala <strong>polova</strong> <strong>rotora</strong> na<br />
temelju komparativna analize <strong>naprezanja</strong>,<br />
Magistarski rad, Zagreb, 1984.<br />
- 73 -