Mea Hana Kūkākūkā Nā Nīnau Hoʻohālike
He mea hana electromagnetic ka mīkini hana e hoʻololi i ka ikehu mechanical i ikehu uila ma o ke kumumanaʻo o ka induction electromagnetic. ʻO nā ʻano mīkini hana i hoʻohana nui ʻia, ʻo ia nā mīkini hana synchronous a me nā mīkini hana asynchronous (a i ʻole induction). E hāʻawi kēia ʻatikala i kekahi mau pilikia hoʻohālike a me nā kūkākūkā e pili ana i nā mīkini hana e hoʻoikaika i ko mākou ʻike i kā lākou mau kumumanaʻo hana, nā ʻāpana, a me nā noi i nā kaapuni uila.
Kumumanaʻo Hana o ka Mea Hana Hana
ʻO ke kumu nui o ka hana ʻana o kahi mīkini hana ua hoʻokumu ʻia ma ke Kānāwai o Faraday no ka Electromagnetic Induction, kahi e ʻōlelo nei ʻo ka loli o ka flux magnetic i loko o kahi loop o ke kaula e hoʻopuka i kahi electromotive force (EMF). Aia kahi mīkini hana i kekahi mau ʻāpana nui:
1. Rotor: ʻO ka ʻāpana e wili ana.
2. Stator: ʻO ka ʻāpana paʻa, kahi e waiho ʻia ai ke uea paʻa a i ʻole ka wili.
3. Kahua Magnetic: Hana ʻia e nā magnet mau loa a i ʻole nā electromagnets.
Nā Nīnau Laʻana a me ke Kūkākūkā
Nīnau 1: Ke helu ʻana i ka Voltage Induced
Nīnau: He 50 mau huli o kahi mīkini hana ma ke kaula stator. Inā he 1200 rpm (nā huli i kēlā me kēia minuke) ka wikiwiki o ka wili ʻana o ka rotor a loli ke kahe magnetic ma o hoʻokahi huli e 0,02 Wb, he aha ka Induced Voltage (EMF) i hana ʻia e ka mīkini hana?
Kūkākūkā: No ka helu ʻana i ka uila i hoʻokomo ʻia hiki iā mākou ke hoʻohana i ka hoʻohālikelike kānāwai o Faraday:
\[ \text{EMF} = -N \frac{d\Phi}{dt} \]
Ma hea:
– ʻO \( N \) ka helu o nā huli,
– ʻO \( \Phi \) ke kahe magnetic, a
– ʻO ka manawa ka \( t \).
ʻO ka hana mua, ʻo ia ka hoʻololi ʻana i ka wikiwiki mai RPM i RPS (nā hoʻololi i kēlā me kēia kekona):
\[ 1200 \text{ RPM} = \frac{1200}{60} \text{ RPS} = 20 \text{ RPS} \]
Hoʻololi ke kahe me kēlā me kēia hoʻohuli ʻana, no laila ua like ke alapine o ka loli ʻana o ke kahe me ke alapine hoʻohuli, ʻo ia hoʻi he 20 Hz. No laila, ʻo ka loli o ke kahe i kēlā me kēia kekona (\( \frac{d\Phi}{dt} \)) penei:
\[ \frac{d\Phi}{dt} = 0,02 \text{ Wb} \times 20 \text{ Hz} = 0,4 \text{ Wb/s} \]
No laila, ʻo ka hopena o ka volta i hoʻokomo ʻia:
\[ \text{EMF} = -50 \times 0,4 \text{ V} = -20 \text{ V} \]
ʻOiai ʻo EMF kahi waiwai paʻa, ʻo ka hopena o ke volta i hoʻokomo ʻia he 20 V.
Nīnau 2: Mana Hoʻopuka Mea Hana
Nīnau: Inā kahe ka mīkini hana ma ka nīnau ma mua ma o kahi ukana resistive o 10 ohms, ehia ka mana uila i hana ʻia?
Kūkākūkā: ʻO ka mea mua, helu mākou i ke au uila me ka hoʻohana ʻana i ke Kānāwai o Ohm:
\[ I = \frac{V}{R} = \frac{20 \text{ V}}{10 \text{ ohm}} = 2 \text{ A} \]
Hiki ke helu ʻia ka mana uila i hana ʻia me ka hoʻohana ʻana i ke ʻano hana:
\[ P = V \times I = 20 \text{ V} \times 2 \text{ A} = 40 \text{ W} \]
No laila, ʻo ka mana uila i hana ʻia he 40 watts.
Nīnau 3: Ka Pono o ka Mea Hana Hana
Nīnau: He 60 watts ka mana hoʻokomo mechanical o kahi mīkini hana a he 45 watts ka mana hoʻopuka uila. He aha ka pono o ka mīkini hana?
Kūkākūkā: Hiki ke helu ʻia ka pono o ka mīkini hana me ka hoʻohana ʻana i ke ʻano hana:
\[ \eta = \frac{P_{\text{out}}}{P_{\text{in}}} \times 100\% \]
Ma hea:
– ʻO \( P_{\text{out}} \) ka mana hoʻopuka uila,
– ʻO \( P_{\text{in}} \) ka mana hoʻokomo mechanical.
No laila, ʻo ka pono:
\[ \eta = \frac{45 \text{ W}}{60 \text{ W}} \times 100\% = 75\% \]
Nīnau 4: Alapine (frequency) o ke anakahi uila AC i hana ʻia
Nīnau: He 4 mau pou o kahi mīkini hana synchronous a hoʻohuli ʻo ia i 1800 rpm. He aha ke alapine (frequency) o ke anakahi uila AC i hana ʻia?
Kūkākūkā: Hiki ke helu ʻia ke alapine (frequency) o ke anakahi uila AC i hana ʻia e kahi mea hana synchronous me ka hoʻohana ʻana i ke ʻano hana:
\[ f = \frac{P \times N}{120} \]
Ma hea:
– ʻO \( P \) ka helu o nā pou,
– ʻO \( N \) ka wikiwiki o ka wili ʻana ma RPM.
E pani i nā waiwai i hāʻawi ʻia:
\[ f = \frac{4 \times 1800}{120} = 60 \text{ Hz} \]
No laila, ʻo ke alapine (frequency) o ke anakahi uila AC i hana ʻia he 60 Hz.
Nīnau 5: Ka wikiwiki o ka Synchronous
Nīnau: E hoʻoholo i ka wikiwiki synchronous o kahi mīkini hana i hoʻopili ʻia i kahi pūnaewele mana 50 Hz a he 6 mau pou.
Kūkākūkā: Hiki ke helu ʻia ka wikiwiki synchronous me ka hoʻohana ʻana i ke ʻano:
\[ N_s = \frac{120 \times f}{P} \]
Ma hea:
– ʻO \( N_s \) ka wikiwiki synchronous ma RPM,
– ʻO \( f \) ke alapine (frequency) ma Hz,
– ʻO \( P \) ka helu o nā pou.
E pani i nā waiwai i hāʻawi ʻia:
\[ N_s = \frac{120 \times 50}{6} = 1000 \text{ RPM} \]
No laila, ʻo ka wikiwiki synchronous o ka mīkini hana he 1000 RPM.
Ka hopena
Ma kēia ʻatikala, ua kūkākūkā mākou i nā kumumanaʻo kumu o ka hana ʻana o ka mīkini hana a ua hōʻike i kekahi mau pilikia hoʻohālike e pili ana i ka helu ʻana o ka volta i hoʻokomo ʻia, ka mana uila, ka pono, ka alapine volta AC, a me ka wikiwiki synchronous. Ma o kēia mau pilikia, ua ʻike mākou pehea e pili ai nā ʻano like ʻole o ka mīkini hana kekahi i kekahi a pehea lākou e hoʻopilikia ai i ka hana holoʻokoʻa. He mea nui ka hoʻomaopopo piha ʻana i kēia mau kumumanaʻo no nā noi hana ma ka ʻenekinia uila.
