Ma transformer amagwira ntchito yofunika kwambiri mu makina ogawa mphamvu zamagetsi, kukweza kapena kutsitsa magetsi kuti akwaniritse zosowa zosiyanasiyana. Pofuna kuonetsetsa kuti ma transformer akugwira ntchito motetezeka komanso modalirika, National Electrical Code (NEC) imakhazikitsa zofunikira zenizeni zowateteza, kuwachotsa, kuwayika pansi, kuwapumitsa, ndi kuwalemba. Nkhaniyi ipereka chithunzithunzi chokwanira cha malamulo a NEC okhudzana ndi chitetezo cha ma transformer, kuphatikizapo chitetezo cha overcurrent, njira zochotsera, kuwayika pansi, kuwapumitsa, ndi zizindikiro za dzina.

Chitetezo cha Overcurrent cha Transformers (NEC 450.3)

Chitetezo chachikulu cha overcurrent

Chitetezo chachikulu cha overcurrent chikufunika kwa ma transformer omwe ali ndi voltage yoyamba ya 1,000 volts kapena kuchepera, pokhapokha ngati transformeryo ikwaniritsa chimodzi mwazosiyana zomwe zalembedwa mu NEC 450.3(A). Chipangizo choteteza primary overcurrent (OCPD) chiyenera kuyesedwa kapena kukhazikitsidwa pa 125% ya primary current yoyesedwa ya transformer. Kwa ma transformer omwe ali ndi ma windings angapo oyamba, winding iliyonse iyenera kukhala ndi OCPD yakeyake.

Chitetezo chachiwiri cha overcurrent

Chitetezo chachiwiri cha overcurrent chikufunika kwa ma transformer omwe ali ndi voltage yachiwiri ya 1,000 volts kapena kuchepera, pokhapokha ngati transformeryo ikwaniritsa chimodzi mwazosiyana zomwe zalembedwa mu NEC 450.3(B). OCPD yachiwiri iyenera kuyesedwa kapena kukhazikitsidwa pa 125% ya secondary current yoyesedwa ndi transformer. Ngati secondary current ili yochepera 9 amperes, OCPD ikhoza kuyesedwa kapena kukhazikitsidwa pa 167% ya secondary current yoyesedwa ndi transformer.

Kupatulapo ndi milandu yapadera

NEC 450.3 imapereka zosiyana zingapo pa zofunikira zotetezera mphamvu yamagetsi yoyambira ndi yachiwiri. Zosiyana izi zimagwira ntchito pa ma configurations ena a transformer, monga ma autotransformer, ndi ma transformer omwe ali ndi mawonekedwe enaake, monga omwe ali ndi impedance yayikulu kapena omwe amagwiritsidwa ntchito m'ma circuits owongolera magalimoto. Ndikofunikira kuwunikanso mosamala NEC 450.3(A) ndi (B) kuti mudziwe ngati transformer ikukwaniritsa zosiyana zilizonse.

Njira Zochotsera Transformer (NEC 450.14)

Malo olumikizira njira

Njira yolumikizira transformer iyenera kukhala pafupi ndi transformer kapena kutali. Ngati ili pamalo akutali, njira yolumikizira iyenera kutsekedwa motsatira NEC 110.25.

Zofunikira zopezeka

Njira zolumikizira transformer ziyenera kukhala zosavuta kuzifikira ndipo siziyenera kukhala pamalo opitilira mamita 2.0 kuchokera pansi kapena papulatifomu yogwirira ntchito, pokhapokha ngati zikwaniritsa chimodzi mwazosiyana zomwe zalembedwa mu NEC 450.14(A).

Zizindikiro zokhazikika

Njira zochotsera transformer ziyenera kukhala ndi chizindikiro chosatha kuti zisonyeze transformer yomwe amayang'anira. Zizindikirozo ziyenera kuwoneka mosavuta ndipo ziyenera kuphatikizapo izi:

• Kuzindikiritsa Transformer (monga, “Transformer T1”)
• Voltage ya transformer ndi ma rating a current
• Malo a transformer (ngati sakuoneka ndi njira yochotsera)

Kuyika Pansi pa Transformer (NEC 450.10)

Kuyika pansi kwa ma transformer enclosures

Ma transformer enclosures ayenera kukhazikitsidwa motsatira NEC 250.4, yomwe imakhazikitsa zofunikira zonse pakukhazikitsa ndi kulumikiza. Choyendetsa pansi chiyenera kukhala ndi kukula kofanana ndi NEC 250.66 ndipo chiyenera kulumikizidwa ku transformer enclosure pogwiritsa ntchito malo oyambira pansi kapena basi.

Kukhazikitsa mabwalo achiwiri a transformer

Ma circuit achiwiri a transformer ayenera kukhazikika motsatira NEC 250.20 ndi 250.30. Njira yokhazikika imatengera mphamvu yamagetsi yachiwiri ya transformer ndi mtundu wa makina amagetsi (monga makina opangidwa mosiyana kapena makina osapangidwa mosiyana). Kawirikawiri, kondakitala ya nthaka iyenera kukhala ndi kukula kofanana ndi NEC 250.66 ndipo iyenera kulumikizidwa ku dera lachiwiri pogwiritsa ntchito malo okhazikika kapena basi.

Kutsegula ndi Kuziziritsa kwa Transformer (NEC 450.9)

Zofunikira pa mpweya wabwino pa ma vault a transformer

Malo osungira mpweya ayenera kukhala ndi mipata yolowera mpweya kuti kutentha komwe kumapangidwa ndi ma transformer kuthe. Malo osungira mpweya ayenera kukhala ndi kukula kogwirizana ndi NEC 450.45 ndipo ayenera kukhalapo kuti mpweya ulowe m'malo osungira mpweya. Nthawi zina, mpweya wolowera mpweya ungafunike kuti kutentha kukhale koyenera mkati mwa malo osungira mpweya.

Zofunikira pa kuziziritsa kwa ma transformer odzazidwa ndi madzi

Ma transformer odzazidwa ndi madzi ayenera kuperekedwa ndi kuziziritsa kokwanira kuti apewe kutentha kwambiri ndikuwonetsetsa kuti ntchito yake ikuyenda bwino. Njira yoziziritsira imatengera kukula kwa transformer ndi mtundu wa madzi omwe amagwiritsidwa ntchito potenthetsera ndi kuziziritsa (monga mafuta amchere, madzi a silicone, kapena madzi osayaka kwambiri). Ma transformer odzazidwa ndi madzi akhoza kuziziritsidwa ndi convection yachilengedwe, kuziziritsa mpweya mokakamizidwa, kapena kusinthana kutentha kwa madzi kukhala madzi. Dongosolo loziziritsira liyenera kupangidwa motsatira malangizo a wopanga transformer ndipo liyenera kukhala lotha kusunga kutentha kwa madzi mkati mwa malire oyenera.

Zizindikiro za Nameplate ya Transformer (NEC 450.11)

Zambiri zofunika pa dzina la plate

Mapepala olembera mawu a transformer ayenera kukhala ndi mfundo zotsatirazi:

• Dzina la wopanga transformer
• Transformer adavotera kilovolt-amperes (kVA)
• pafupipafupi
• Voliyumu yoyamba ndi yachiwiri
• Impedance (ngati 25 kVA kapena kuposerapo)
• Malo ofunikira kuti mpweya ulowe
• Kuchuluka ndi mtundu wa madzi oteteza kutentha (a ma transformer odzazidwa ndi madzi)
• Kuyesa kwa BIL kwa ma winding amphamvu kwambiri (kwa ma transformer okhala ndi ma winding amphamvu kwambiri opitilira 1,000 volts)

Kulimba kwa zilembo za mayina

Mapepala olembera dzina a transformer ayenera kupangidwa ndi zinthu zolimba zomwe zimatha kupirira malo omwe transformer imayikidwa. Mapepala olembera dzina ayenera kumangiriridwa bwino ku transformer ndipo ayenera kuwerengedwa nthawi yonse ya transformer.