Lub hauv paus ntsiab lus tseem ceeb ntawm cov roj-immersed transformer yog ua raws li electromagnetic induction: thaum lub hauv paus winding txuas nrog AC lub zog, qhov sib nqus sib nqus flux yog tsim nyob rau hauv cov tub ntxhais hlau, thiab qhov voltage yog induced nyob rau hauv lub thib ob winding vim qhov kev hloov ntawm magnetic flux. Nws cov qauv tsuas yog muaj cov tub ntxhais hlau, windings, insulating roj, thiab roj tank.
Cov tub ntxhais hlau yog ua los ntawm laminated siab -permeability silicon steel los xij kom txo tau qhov poob tam sim no; cov windings yog ua los ntawm tooj liab lossis txhuas hlau thiab muab faib ua high-voltage thiab low-voltage windings kom ua tiav qhov hloov pauv voltage; cov roj insulating tsis tsuas yog sau cov roj tank kom cais cov huab cua, tab sis kuj tshem tawm cov cua sov uas tsim los ntawm cov cua kub thiab cov tub ntxhais hlau los ntawm kev ncig, tswj kev ua haujlwm ruaj khov.