The invention relates to the field of automobile alternating-current generators, and discloses a high-power alternating-
current generator which comprises a
machine shell, a rear end cover arranged behind the
machine shell and a built-in
machine shaft. A heat dissipation hole is formed in the rear end cover, a rotating block with a first
fan blade is arranged in the hole, and the rotating block is rotationally installed on a supporting frame fixed to the rear end cover; a connecting groove is formed in the transmission shaft, the main shaft is inserted into the groove and is in transmission connection with the groove, and two ends of memory
alloy in the groove are fixedly connected with the main shaft and the transmission shaft; the rotating block and the transmission shaft are in
clutch transmission through the second
butt joint assembly. A sliding sleeve with a second
fan blade is arranged between the first
fan blade and the second fan blade, is provided with a through hole and is in
clutch transmission with the transmission shaft through a first butt-joint
assembly; the sliding sleeve is provided with a groove, the rotating block is rotatably provided with a connecting rotating ring, the connecting rotating ring is fixedly connected with a supporting rod, and the supporting rod is inserted into the inserting groove. A mechanism for driving the transmission shaft to move is arranged between the transmission shaft and the sliding sleeve. After the temperature in the alternating-
current generator rises, the transmission shaft drives the rotating block and the first fan blade through the second
butt joint assembly, the two fan blades are stacked for heat dissipation, and the high-temperature requirement is met.