Nā kumu kumu o nā mīkini DC a me AC
ʻO ka mīkini uila kahi mea hana e hoʻololi i ka ikehu mai kekahi ʻano a i kekahi ma o nā loina o ka electromagnetism. I loko o ka ʻenekinia uila, ʻo nā hui mīkini ʻelua maʻamau a kūkākūkā pinepine ʻia ʻo ia nā mīkini DC (direct current) a me nā mīkini AC (alternating current). Hiki i nā mea ʻelua ke hana ma ke ʻano he mau motika (e hoʻololi ana i ka ikehu uila i ka ikehu mechanical) a i ʻole nā mea hana (e hoʻololi ana i ka ikehu mechanical i ka ikehu uila). Kūkākūkā kēia ʻatikala i nā manaʻo kumu, ke kūkulu ʻana, nā loina hana, a me nā ʻokoʻa koʻikoʻi ma waena o nā mīkini DC a me AC.
1. Nā Manaʻo Kumu o nā Mīkini Uila
ʻO ke kumu nui o ka hana o kahi mīkini uila e pili ana i ʻelua mau kumumanaʻo nui:
1. Ka ikaika Lorentz: ʻike kahi alakaʻi e lawe ana i ke au i loko o kahi kahua magnetic i kahi ikaika. ʻO kēia ke kumu o ka hana ʻana o kahi motika, kahi e hana ai ka ikaika magnetic i kahi torque e hoʻohuli i ka rotor.
2. Hoʻokomo uila (Ke Kānāwai o Faraday): kahi loli o ke kahe magnetic ma waena o kahi alakaʻi e hana i kahi volta i hoʻokomo ʻia. ʻO kēia ke kumu o ka hana ʻana o kahi mīkini hana, kahi e hana ai ka wili mechanical i kahi volta uila.
I nā huaʻōlelo ʻē aʻe, hoʻohana ka mīkini uila i ka pilina o nā kahua magnetic a me nā au uila e hana i ka neʻe ʻana, a i ʻole, e hana i ka uila mai ka neʻe ʻana.
2. Mīkini DC (Direct Current)
2.1 Wehewehena a me nā ʻano
He mīkini uila ka mīkini DC e hana ana ma kahi kumu au pololei (DC). Ua kaulana kēia mau mīkini no ko lākou maʻalahi o ka wikiwiki a me ka kaohi ʻana i ka torque. Eia nō naʻe, ʻoi aku ka paʻakikī o ka mālama ʻana i ka hoʻohana ʻana i nā commutators a me nā pulumu ma mua o nā mīkini AC he nui.
2.2 Ke Kūkulu Nui ʻana o ka Mīkini DC
Ma keʻano laulā, aia kahi mīkini DC i:
– Stator (ʻāpana paʻa): hana i kahi kahua makeneti. Hiki ke hoʻokumu ʻia kahi kahua makeneti e:
– Nā wili kahua ma nā pou stator, a i ʻole
– Nā makeneka paʻa (i loko o nā motika DC liʻiliʻi).
– Rotor/Armature (ʻāpana wili): kahi i loaʻa ai ke kaula armature. Ma kēia kaula, hana ʻia ke kahe uila a me ke kahe o ke au i hoʻokomo ʻia, kahi e hana ai i ka torque.
– Commutator: kahi ʻāpana ma ke ʻano o ke apo i ʻāpana ʻia e hana ana e hoʻohuli i ke kuhikuhi o ke au i loko o ka ʻōwili rotor i mau ai ka torque ma ke kuhikuhi like.
– Palaki: he alakaʻi (ʻo ke kalapona maʻamau) e hoʻokahe i ke au mai ke kumu a i ka commutator.
2.3 Kumumanaʻo Hana o ka Motika DC
Ke kahe ke au ma o nā wili rotor i loko o ke kahua magnetic o ka stator, hoʻokumu ʻia kahi ikaika Lorentz ma luna o nā alakaʻi. Hoʻokumu kēia ikaika i ka torque, e hoʻohuli ana i ka rotor. No ka mālama ʻana i ka wili me kahi kuhikuhi torque kūlike, hoʻohuli ka commutator i ka pilina o kēia manawa i kēlā me kēia hapalua hoʻohuli.
Hoʻopilikia ʻia ka wikiwiki o ka motika DC e:
– Ka nui o ke anakahi heleuma,
- Ka nui o ke kahe ʻana o ke kahua,
– Ka ukana mīkini.
Hiki ke hana maʻalahi ʻia ka kaohi ʻana i ka wikiwiki o ka motika DC, no ka laʻana ma ka hoʻololi ʻana i ke volta hoʻokomo a i ʻole ke hoʻoponopono ʻana i ke au o ke kahua.
2.4 Kumumanaʻo Hana o ka Mea Hana DC
Ke hoʻohuli ʻia ka rotor e kahi kumu mechanical (e.g., he turbine), ʻoki nā ʻōwili rotor i ke kahe magnetic, e hana ana i kahi voltage induced (AC, ma ke ʻano maoli). A laila hoʻoponopono ka commutator i ka hopena, e hopena ana i kahi hoʻopuka DC ma nā kikowaena.
2.5 Nā ʻAno o nā Mīkini DC
Hoʻokaʻawale pinepine ʻia nā mīkini DC e ke ʻano o ka hoʻonāukiuki kahua:
– Shunt: ʻōwili kahua e kūlike ana me ka heleuma (wikiwiki paʻa).
– Moʻo: wili kahua ma ke moʻo me ka armature (torque mua nui).
– Hui: kahi hui pū ʻana o ka shunt a me ka series (kahi hoʻohālikelike ma waena o ka torque mua a me ke kūpaʻa).
– Hoʻonāukiuki ʻokoʻa: nā kumu kahua kaʻawale (mana ʻoi aku ka maʻalahi).
3. Mīkini AC (Aupuni ʻAla)
3.1 Wehewehena a me nā ʻano
He mīkini uila ka mīkini AC e hana ana ma ke au uila. ʻOi aku ka nui o nā mīkini AC ma mua o nā noi ʻoihana no ka mea he maʻalahi lākou (ʻoi aku hoʻi nā mīkini induction), ʻoi aku ka ikaika, a ʻoi aku ka liʻiliʻi o ka mālama ʻana. Loaʻa nā mīkini AC i ʻelua ʻano nui: nā mīkini synchronous a me nā mīkini induction (asynchronous).
3.2 Ke kūkulu ʻana o ka mīkini AC
ʻO nā ʻāpana kumu o kahi mīkini AC e komo pū me kahi stator a me kahi rotor:
– Stator: loaʻa iā ia nā wili ʻekolu-pae (ma ka hapa nui o nā noi ʻoihana) e hana ana i kahi kahua magnetic wili.
– Rotor: pili ke ʻano rotor i ke ʻano o ka mīkini:
– ʻO ka rotor squirrel cage i loko o kahi motika induction he mau ʻauamo alakaʻi i hoʻopuni pōkole ʻia me nā apo.
– ʻO ka rotor ʻōwili i loko o kekahi mau mīkini induction e ʻae i ka hoʻohui ʻana o ke kū'ē o waho.
– ʻO ka rotor pou (rotor kahua) i nā mīkini synchronous (hiki i ke kahua rotor ke hana ʻia mai ke au DC a i ʻole ka magnet mau loa).
3.3 Ke Kahua Magnetic e Hoʻohuli ana
ʻO ka hiʻohiʻona kūikawā o kahi mīkini AC ʻekolu-paepae ʻo ia ka hiki o ka stator ke hoʻoulu kūlohelohe i kahi kahua magnetic wili. Ke kahe ke au ʻekolu-paepae ma o nā wili stator, wili ke kahua magnetic i kahi wikiwiki kikoʻī, i kapa ʻia ʻo ka wikiwiki synchronous:
\[
n_s = \frac{120 f}{P}
\]
Ma hea:
– \( n_s \) = ka wikiwiki like (rpm),
– \( f \) = alapine (Hz),
– \( P \) = ka helu o nā pou.
Hoʻoholo kēia wikiwiki i nā ʻano kumu o kahi motika AC.
4. Motika Hoʻokomo (Asynchronous)
4.1 Kumu Hana
Hana nā motika hoʻokomo ma ke kumumanaʻo o ka hoʻokomo electromagnetic. ʻOki ke kahua stator wili ma o nā alakaʻi rotor, e hana ana i kahi au i hoʻokomo ʻia i loko o ka rotor. Hoʻopuka kēia au rotor i kahi kahua magnetic rotor e launa pū me ke kahua stator, e hana ana i ka torque.
ʻAʻole hiki i ka rotor o kahi motika induction i ka wikiwiki synchronous. ʻO ka ʻokoʻa ma waena o ka wikiwiki o ka rotor a me ka wikiwiki synchronous ua kapa ʻia ʻo slip:
\[
s = \frac{n_s – n_r}{n_s}
\]
He mea pono ka pahee no ka hoʻomau ʻana o ke kaʻina hana hoʻokomo.
4.2 Nā Pōmaikaʻi a me nā Palena
Pono:
- Kūkulu maʻalahi a paʻa hoʻi,
– Mālama haʻahaʻa,
- Ke kumu kūʻai haʻahaʻa, kūpono no ka ʻoihana.
Ke palena:
- ʻAʻole maʻalahi ka kaohi wikiwiki e like me ka motika DC me ka ʻole o nā mea hana ʻē aʻe,
– Hiki ke nui ke au hoʻomaka (koi i kahi ʻano hoʻomaka kikoʻī a i ʻole inverter/VFD).
5. Mīkini Hoʻohui
5.1 Kumu Hana
I loko o kahi mīkini synchronous, hoʻohuli ka rotor i ka wikiwiki like me ke kahua hoʻohuli o ka stator. Loaʻa i ka rotor kahi kahua magnetic (mai ke au DC ma o nā apo paheʻe a i ʻole nā magnets mau loa) e "laka" me ke kahua stator.
5.2 Nā noi
– ʻO nā mea hana synchronous (alternators) i loko o nā mea kanu mana ka mea maʻamau, no ka mea, hana lākou i kahi uila AC paʻa.
– Hoʻohana ʻia nā motika synchronous no nā noi e pono ai ka wikiwiki mau a me ka pono kiʻekiʻe, a me ka mana mana hiki ke hoʻololi ʻia (ʻoi aku hoʻi me ka kaohi hoʻonāukiuki).
6. Hoʻohālikelike ʻana o nā mīkini DC a me AC
1. Kumu a me ka Hoʻopuka
– Nā mīkini DC: Hoʻokomo/hoʻopuka DC, me ka hoʻohana ʻana i kahi commutator no ka hoʻoponopono mechanical.
– Nā mīkini AC: Hoʻokomo/hoʻopuka AC, ma ke ʻano laulā me ka ʻole o ka commutator (koe wale nō kekahi mau ʻano kūikawā).
2. Mālama
– DC: ʻoi aku ke kiʻekiʻe ma muli o ka ʻaʻahu ʻana o ka palaki a me ka commutator.
– AC (induction): haʻahaʻa no ka mea ʻaʻole ia e hoʻohana i nā pulumu (no nā rotors cage).
3. Mana wikiwiki
– DC: maʻalahi a ākea nā hoʻonohonoho.
– AC: ʻoi aku ka paʻakikī, akā i kēia manawa ua kōkua nui ʻia e VFD/inverter.
4. Noi
– DC: kekahi mau kaʻa uila, nā lako e pono ai ka kaohi torque/wikiwiki pololei (i kekahi mau hoʻolālā), nā ʻōnaehana hoʻokele kahiko.
– AC: nā motika ʻoihana, nā pamu, nā mea pā, nā compressors, ka hana mana (nā mea hana synchronous).
7. Hopena
Hoʻohana nā mīkini DC a me AC i ka launa pū ʻana o nā kahua magnetic a me nā au uila, akā ʻokoʻa lākou i ke ʻano o ka hoʻoulu ʻana i ka torque, ke kūkulu ʻana, a me nā ʻano hana. ʻOi aku ka maikaʻi o nā mīkini DC i ka maʻalahi o ka hoʻokele ʻana, akā koi aku i ka mālama hou aku ma muli o ka commutator a me nā pulumu. ʻO nā mīkini AC, ʻoi aku ka induction motors, ke kumu o ka ʻoihana ma muli o ko lākou maʻalahi, ka lōʻihi, a me ka hoʻokele waiwai. ʻO ka hoʻomaopopo ʻana i nā kumu o nā ʻano mīkini ʻelua he mea nui ia ma mua o ke komo ʻana i nā kumuhana holomua e like me ka hoʻokele wikiwiki me nā inverters, nā ʻōnaehana hoʻokele, a me ka nānā ʻana i ka hana a me ka pono o nā mīkini uila.
Inā makemake ʻoe, hiki iaʻu ke hana i kahi mana loea (me nā kiʻi manaʻo a me nā laʻana helu maʻalahi) a i ʻole kahi mana maʻalahi no nā haumāna ʻoihana/kula kiʻekiʻe.
