Thermal relay yog ib qho khoom siv hluav taws xob uas tiv thaiv lub tshuab hluav taws xob ntawm txhua yam khoom siv hluav taws xob los ntawm qhov kub thiab txias. Nyob rau hauv cov xwm txheej hnyav ntxiv, lub cav, uas tau teeb tsa hauv cov lus tsa suab ntawm lub tshuab hluav taws xob lossis cov khoom siv hluav taws xob, siv hluav taws xob ntau ntxiv. Lub zog no tuaj yeem ua tau ntau zaus ntau dua li cov qauv sau rau lub cav. Raws li qhov tshwm sim ntawm cov txheej txheem overload, qhov kub hauv qhov hluav taws xob hluav taws xob pib nce sai. Qhov no, ntawm chav kawm, yuav zoo ua rau kev puas tsuaj ntawm cov khoom siv hluav taws xob no. Txhawm rau tiv thaiv qhov no, cov cuab yeej tshwj xeeb ntxiv tau suav nrog hauv cov hluav taws xob hluav taws xob, tsim los txiav tawm cov khoom siv hluav taws xob thaum muaj xwm txheej ceev (kev hloov pauv hauv cov khoom siv hluav taws xob, overloads, thiab lwm yam). Xws li cov cuab yeej tiv thaiv hu ua thermal relay (qee zaum koj tuaj yeem pom lub npe "thermal relay" hauv cov ntawv nyeem). Lub luag haujlwm tseem ceeb ntawm cov thermal relay yog tswj hwm kev ua haujlwm ntawm cov khoom siv hluav taws xob thiab nws qhov kev ua tau zoo tag nrho.
Thermal relay muaj nyob rau hauv nws sab hauvtsim ib lub phaj tshwj xeeb bimetallic. Nyob rau hauv kev cuam tshuam ntawm overloads thiab nce voltage nyob rau hauv hluav taws xob network, xws li ib tug phaj khoov (deforms), thiab nyob rau hauv nws ib txwm lub xeev nws muaj ib tug ncaj tiaj tus. Cov phaj bimetallic no kaw cov hluav taws xob tiv tauj kom nruj, thiab yog li tam sim no tuaj yeem ntws tawm los ntawm hluav taws xob hluav taws xob.
Thaum muaj qhov overvoltage thiab nce tus nqi ntawm cov hluav taws xob tam sim no hauv Circuit Court pib ua kom kub ceev. Qhov no ua rau cov cua sov ntawm lub ntsiab tseem ceeb ntawm thermal relay - ob txheej hlau phaj. Lub tom kawg pib khoov thiab rhuav tshem cov hluav taws xob ntws, vim tias lub thermal relay yog tsim los txiav tawm qhov load thiab voltage thaum lub network hluav taws xob overloaded.
Txawm li cas los xij, lub phaj bimetallic khoov qeeb qeeb. Yog hais tias qhov kev sib cuag yog txav tau thiab txuas ncaj qha mus rau nws, ces qhov qis deflection tus nqi yuav tsis xyuas kom meej lub extinction ntawm arc uas tshwm sim thaum lub Circuit Court tawg. Yog li ntawd, tus tsim ntawm lub thermal relay muab rau ib tug accelerating ntaus ntawv, lub thiaj li hu ua "dhia hu". Nws ua raws li qhov kev xaiv ntawm lub thermal relay yog raws li tus yam ntxwv xws li kev cia siab ntawm lub sij hawm teb ntawm qhov loj ntawm cov hluav taws xob tam sim no.
Vim qhov sib txawv li ntawd, kev ua haujlwm ntawm lub tshuab yuav raug tso tseg. Tom qab qee lub sijhawm (feem ntau ib nrab ib teev - ib teev), lub phaj txias thiab rov qab mus rau nws lub xeev dhau los, uas rov ua haujlwm ntawm cov hluav taws xob hluav taws xob hluav taws xob. Cov cuab yeej rov qab los ua haujlwm.
Muaj ntau hom thermal relay. TRP relay (rau ib-theem load), TRN relay (rau ob-theem load), thermal relay PTT (rau lub sij hawm ntev overload nyob rau hauv peb-theem Circuit Court) thiab thermal relay RTL (tiv thaiv hluav taws xob. motors los ntawm lub sij hawm overloads) tau dhau mus.
