mˈuːvɪŋ ðə lˈoʊd dˈɪsk ɐlˈɔŋ ðɪs ʃˈæft tʃˈeɪndʒᵻz ðə ɹˈeɪʃɪˌoʊ ʌv ˈɪnpʊt tʊ ˈaʊtpʊt spˈiːd; wˌɛn ðə lˈoʊd dˈɪsk ɪz æt ðə sˈɛntɚ ðɪ ˈaʊtpʊt ɪz zˈiəɹoʊ, wˌɛn ɪɾ ɪz æt ðɪ ˈaʊɾɚ ɹˈɪm, ɪɾ ɪz ðə ɹˈeɪʃɪˌoʊ ʌvðə ɹˈeɪdɪəs ʌvðə tˈuː dˈɪsks.
Moving the load disk along this shaft changes the ratio of input to output speed; when the load disk is at the center the output is zero, when it is at the outer rim, it is the ratio of the radius of the two disks.