Novel three-phase three-speed motor controller

A novel three-phase three-speed motor controller disclosed by the present invention comprises a shell and a cavity located in the shell, the cavity is internally provided with a vapor-liquid conversion heat dissipation mechanism extending to the outside, the vapor-liquid conversion heat dissipation mechanism comprises a plurality of U-shaped pieces, and one side of the shell is provided with an air cooling mechanism acting on the U-shaped pieces. Round openings communicated with the outside are symmetrically formed in the top of the cavity, the U-shaped piece comprises an arc-shaped part located in the cavity and a tubular part penetrating through the round openings to extend to the outside, the U-shaped piece is filled with liquid ammonia, a plurality of cooling fins are arranged on the tubular part, and a temperature control circuit used for controlling the air cooling mechanism to be started and stopped is arranged on the shell. The air cooling mechanism comprises a motor M located at the top of the shell,