Lo lus commutator yog qee zaum yuam kev siv rau qhov chaw ntawm lub nplhaib ntiv nplhaib. Lub commutator yog ib lub nplhaib tshwj xeeb uas feem ntau siv rau ntawm Direct Current motors thiab cov khoom siv hluav taws xob los hloov hluav taws xob hluav taws xob ntawm lub tsev nyob ruaj khov thiab cov khoom sib hloov nrog lub hom phiaj ntxiv ntawm kev thim rov qab cov hluav taws xob tam sim no.
Lub nplhaib commutator yog ua los ntawm cov hlau nplaum uas tsis zoo li lub nplhaib hlau ntawm lub nplhaib plam. Cov txhuam hluav taws xob (sib cuag) rub ntawm lub nplhaib tig los ua qhov sib txuas hluav taws xob. Cov ntiv nplhaib ntu no yog xaim los ua qhov hloov pauv txhawm rau txhawm rau thim rov qab cov hluav taws xob tam sim no. Hauv DC lub cev muaj zog qhov kev hloov pauv hloov pauv cov hlau nplaum kom lub cev muaj zog tig. Hauv lub tshuab hluav taws xob hloov pauv hloov pauv tam sim no mus rau tam sim no ntws hauv ib qho kev taw qhia (DC).