Chitsanzo cha Mafunso Okambirana
Jenereta ndi chipangizo chamagetsi chomwe chimasintha mphamvu yamakina kukhala mphamvu yamagetsi pogwiritsa ntchito mfundo ya induction yamagetsi. Mitundu ya majenereta omwe amagwiritsidwa ntchito kwambiri ndi majenereta ogwirizana ndi majenereta osasinthasintha (kapena osakanikirana). Nkhaniyi ipereka zitsanzo zingapo za mavuto ndi zokambirana zokhudza majenereta kuti timvetsetse bwino mfundo zawo zogwirira ntchito, zigawo zake, ndi momwe amagwiritsidwira ntchito m'mabwalo amagetsi.
Mfundo Yogwirira Ntchito ya Jenereta
Mfundo yaikulu ya momwe jenereta imagwirira ntchito imachokera ku lamulo la Faraday la Electromagnetic Induction, lomwe limati kusintha kwa maginito flux mu kuzungulira kwa waya kumapanga mphamvu ya electromotive (EMF). Jenereta imakhala ndi zigawo zingapo zazikulu:
1. Chozungulira: Gawo lozungulira.
2. Stator: Gawo losasuntha, komwe waya wolimba kapena coil imayikidwa.
3. Magnetic Field: Yopangidwa ndi maginito okhazikika kapena maginito amagetsi.
Mafunso ndi Kukambirana Zitsanzo
Funso 1: Kuwerengera Mphamvu Yoyambitsa
Funso: Jenereta imakhala ndi ma turn 50 pa stator coil. Ngati liwiro la rotor rotation ndi 1200 rpm (ma rotations pa mphindi) ndipo ma magnetic flux kudzera mu turn imodzi amasintha ndi 0,02 Wb, kodi Induced Voltage (EMF) yopangidwa ndi jenereta ndi chiyani?
Kukambirana: Kuti tiwerengere mphamvu yamagetsi yomwe yayambitsidwa, tingagwiritse ntchito equation ya Faraday's Law:
\[ \text{EMF} = -N \frac{d\Phi}{dt} \]
Kumene:
– \( N \) ndi chiwerengero cha ma turn,
– \( \Phi \) ndi maginito othamanga, ndipo
– \(t \) ndi nthawi.
Gawo loyamba ndikusintha liwiro kuchokera ku RPM kupita ku RPS (kuzungulira pa sekondi):
\[ 1200 \malemba{ RPM} = \frac{1200}{60} \malemba{ RPS} = 20 \malemba{ RPS} \]
Kusintha kwa madzi kumasintha ndi kusintha kulikonse, kotero kuchuluka kwa kusintha kwa madzi kumakhala kofanana ndi kuchuluka kwa madzi komwe kumazungulira, komwe ndi 20 Hz. Chifukwa chake, kusintha kwa madzi pa sekondi (\( \frac{d\Phi}{dt} \)) ndi:
\[ \frac{d\Phi}{dt} = 0,02 \text{ Wb} \times 20 \text{ Hz} = 0,4 \text{ Wb/s} \]
Chifukwa chake, mphamvu yamagetsi yomwe imabwera chifukwa cha izi ndi:
\[ \malemba{EMF} = -50 \nthawi 0,4 \malemba{V} = -20 \malemba{V} \]
Popeza EMF ndi mtengo wokwanira, mphamvu yamagetsi yomwe imabwera chifukwa cha izi ndi 20 V.
Funso 2: Mphamvu Yotulutsa Jenereta
Funso: Ngati jenereta mu funso lapitali ikuyenda kudzera mu katundu wotsutsa wa 10 ohms, kodi mphamvu zamagetsi zingati zimapangidwa?
Kukambirana: Choyamba, timawerengera mphamvu yamagetsi pogwiritsa ntchito lamulo la Ohm:
\[ I = \frac{V}{R} = \frac{20 \text{ V}}{10 \text{ ohm}} = 2 \text{ A} \]
Mphamvu yamagetsi yopangidwa ikhoza kuwerengedwa pogwiritsa ntchito fomula iyi:
\[ P = V \nthawi I = 20 \malemba{ V} \nthawi 2 \malemba{ A} = 40 \malemba{ W} \]
Chifukwa chake, mphamvu yamagetsi yopangidwa ndi 40 watts.
Funso 3: Kugwiritsa Ntchito Moyenera kwa Jenereta
Funso: Jenereta ili ndi mphamvu yolowera yamakina ya ma watts 60 ndi mphamvu yotulutsa yamagetsi ya ma watts 45. Kodi jeneretayo imagwira ntchito bwanji bwino?
Kukambirana: Kugwiritsa ntchito bwino kwa jenereta kungawerengedwe pogwiritsa ntchito fomula iyi:
\[ \eta = \frac{P_{\text{out}}}{P_{\text{in}}} \times 100\% \]
Kumene:
– \( P_{\text{out}} \) ndi mphamvu yamagetsi yotulutsa,
– \( P_{\text{in}} \) ndi mphamvu yolowera yamakina.
Chifukwa chake magwiridwe antchito ndi awa:
\[ \eta = \frac{45 \text{ W}}{60 \text{ W}} \times 100\% = 75\% \]
Funso 4: Kuchuluka kwa Voltage ya AC Yopangidwa
Funso: Jenereta yolumikizana ili ndi ma poles anayi ndipo imazungulira pa 1800 rpm. Kodi ma frequency a AC voltage amapangidwa ndi otani?
Kukambirana: Kuchuluka kwa magetsi a AC opangidwa ndi jenereta yolumikizana kungawerengedwe pogwiritsa ntchito fomula iyi:
\[ f = \frac{P \times N}{120} \]
Kumene:
– \( P \) ndi chiwerengero cha mitengo,
– \( N \) ndi liwiro lozungulira mu RPM.
M'malo mwa mfundo zomwe zaperekedwa:
\[ f = \frac{4 \times 1800}{120} = 60 \text{ Hz} \]
Chifukwa chake, ma frequency a AC voltage omwe amapangidwa ndi 60 Hz.
Funso 5: Liwiro Lofanana
Funso: Dziwani liwiro logwirizana la jenereta yolumikizidwa ku gridi yamagetsi ya 50 Hz komanso yokhala ndi mipiringidzo 6.
Kukambirana: Liwiro logwirizana likhoza kuwerengedwa pogwiritsa ntchito fomula iyi:
\[ N_s = \frac{120 \times f}{P} \]
Kumene:
– \( N_s \) ndi liwiro logwirizana mu RPM,
– \( f \) ndi mafupipafupi mu Hz,
– \( P \) ndi chiwerengero cha mipiringidzo.
M'malo mwa mfundo zomwe zaperekedwa:
\[ N_s = \frac{120 \nthawi 50}{6} = 1000 \malemba{ RPM} \]
Kotero, liwiro la synchronous la jenereta ndi 1000 RPM.
Mapeto
Munkhaniyi, takambirana mfundo zoyambira za ntchito ya jenereta ndipo tapereka zitsanzo zingapo za mavuto okhudzana ndi kuwerengera mphamvu yamagetsi yoyambitsidwa, mphamvu yamagetsi, magwiridwe antchito, kuchuluka kwa mphamvu yamagetsi ya AC, ndi liwiro logwirizana. Kudzera mu mavutowa, tawona momwe magawo osiyanasiyana a jenereta amagwirizanirana komanso momwe amakhudzira magwiridwe antchito onse. Kumvetsetsa bwino mfundozi ndikofunikira pakugwiritsa ntchito bwino uinjiniya wamagetsi.
