Misalan Tambayoyi Masu Samar da Tattaunawa
Janareta na'urar lantarki ce da ke canza makamashin injiniya zuwa makamashin lantarki ta hanyar amfani da na'urar lantarki. Nau'ikan janareta da aka fi amfani da su sune janareta masu aiki da juna da kuma janareta masu aiki da asynchronous (ko induction). Wannan labarin zai samar da misalai da dama na matsaloli da tattaunawa game da janareta don zurfafa fahimtarmu game da ka'idojin aikinsu, abubuwan da aka haɗa, da aikace-aikacensu a cikin da'irar lantarki.
Ka'idar Aiki da Janareta
Babban ƙa'idar yadda janareta ke aiki ta dogara ne akan Dokar Faraday ta Induction na Electromagnetic, wadda ta bayyana cewa canjin kwararar maganadisu a cikin madaurin waya zai samar da ƙarfin lantarki (EMF). Janareta ya ƙunshi manyan abubuwa da yawa:
1. Na'urar Juyawa: Sashen juyawa.
2. Stator: Sashen da ba ya tsayawa, inda aka sanya waya ko na'urar da ke aiki da ƙarfi.
3. Filin Magnetic: Ana samar da shi ta hanyar maganadisu na dindindin ko na lantarki.
Tambayoyi da Tattaunawa Samfura
Tambaya ta 1: Lissafin Wutar Lantarki Mai Inganci
Tambaya: Janareta yana da juyawa 50 a kan na'urar stator. Idan saurin juyawar rotor shine 1200 rpm (juyawa a minti daya) kuma kwararar maganadisu ta juyawa daya ta canza da 0,02 Wb, menene Induced Voltage (EMF) da janareta ke samarwa?
Tattaunawa: Don ƙididdige ƙarfin lantarki da aka haifar za mu iya amfani da lissafin Dokar Faraday:
\[ \text{EMF} = -N \frac{d\Phi}{dt} \]
Ina:
– \( N \) shine adadin juyawa,
– \( \Phi \) shine kwararar maganadisu, kuma
– \( t \) lokaci ne.
Mataki na farko shine a canza saurin daga RPM zuwa RPS (juyawa a cikin daƙiƙa ɗaya):
\[ 1200 \rubutu{ RPM} = \frac{1200}{60} \rubutu{ RPS} = 20 \rubutu{ RPS} \]
Ruwan yana canzawa da kowace juyawa, don haka mitar canjin ruwan yana daidai da mitar juyawa, wanda shine 20 Hz. Don haka, canjin ruwan a kowace daƙiƙa (\( \frac{d\Phi}{dt} \)) shine:
\[ \frac{d\Phi}{dt} = 0,02 \text{ Wb} \times 20 \text{ Hz} = 0,4 \text{ Wb/s} \]
Saboda haka, sakamakon ƙarfin lantarki da aka haifar shine:
\[ \text{EMF} = -50 \times 0,4 \text{ V} = -20 \text{ V} \]
Tunda EMF cikakkiyar ƙima ce, ƙarfin lantarki da aka haifar shine 20 V.
Tambaya ta 2: Ƙarfin Fitar da Janareta
Tambaya: Idan janareta a cikin tambayar da ta gabata tana gudana ta hanyar nauyin juriya na 10 ohms, nawa ne wutar lantarki da ake samarwa?
Tattaunawa: Da farko, muna ƙididdige wutar lantarki ta amfani da Dokar Ohm:
\[ I = \frac{V}{R} = \frac{20 \text{ V}}{10 \text{ ohm}} = 2 \text{ A} \]
Ana iya ƙididdige wutar lantarki da aka samar ta amfani da dabarar:
\[ P = V \times I = 20 \text{ V} \times 2 \text{ A} = 40 \text{ W} \]
Saboda haka, wutar lantarki da ake samarwa watts 40 ne.
Tambaya ta 3: Ingantaccen Injin Samar da Janareta
Tambaya: Janareta yana da ƙarfin shigarwa na inji na watt 60 da kuma ƙarfin fitarwa na watt 45. Menene ingancin janareta?
Tattaunawa: Ana iya ƙididdige ingancin janareta ta amfani da dabarar:
\[ \eta = \frac{P_{\text{out}}}{P_{\text{in}}} \times 100\% \]
Ina:
– \( P_{\text{out}} \) shine ƙarfin fitarwa na lantarki,
– \( P_{\text{in}} \) shine ƙarfin shigarwar inji.
Don haka ingancin shine:
\[ \eta = \frac{45 \text{ W}}{60 \text{ W}} \times 100\% = 75\% \]
Tambaya ta 4: Mitar ƙarfin lantarki na AC da aka samar
Tambaya: Injin janareta mai aiki da wutar lantarki yana da sanduna 4 kuma yana juyawa a 1800 rpm. Menene mitar ƙarfin wutar lantarki na AC da aka samar?
Tattaunawa: Ana iya ƙididdige mitar ƙarfin lantarki na AC da janareta mai daidaitawa ke samarwa ta amfani da dabarar:
\[ f = \frac{P \times N}{120} \]
Ina:
– \( P \) shine adadin sandunan,
– \( N \) shine saurin juyawa a cikin RPM.
Maye gurbin dabi'un da aka bayar:
\[ f = \frac{4 \times 1800}{120} = 60 \text{ Hz} \]
Don haka, mitar ƙarfin lantarki na AC da aka samar shine 60 Hz.
Tambaya ta 5: Saurin Daidaitawa
Tambaya: Kayyade saurin daidaitawa na janareta da aka haɗa zuwa grid ɗin wutar lantarki na 50 Hz kuma yana da sanduna 6.
Tattaunawa: Ana iya ƙididdige saurin daidaitawa ta amfani da dabarar:
\[ N_s = \frac{120 \sau f}{P} \]
Ina:
– \(N_s \) shine saurin daidaitawa a cikin RPM,
– \( f \) shine mitar a cikin Hz,
– \( P \) shine adadin sandunan.
Maye gurbin dabi'un da aka bayar:
\[ N_s = \frac{120 \sau 50}{6} = 1000 \text{ RPM} \]
Saboda haka, saurin daidaitawar janareta shine 1000 RPM.
Kammalawa
A cikin wannan labarin, mun tattauna ƙa'idodin aikin janareta kuma mun gabatar da misalai da yawa na matsaloli waɗanda suka shafi lissafin ƙarfin lantarki da aka haifar, wutar lantarki, inganci, mitar ƙarfin AC, da saurin daidaitawa. Ta hanyar waɗannan matsalolin, mun ga yadda sigogin janareta daban-daban ke da alaƙa da juna da kuma yadda suke shafar aiki gaba ɗaya. Fahimtar waɗannan ƙa'idodi yana da mahimmanci ga aikace-aikacen aikace-aikace a cikin injiniyan lantarki.
