Protective device of motor driver

The utility model discloses a protective device of a motor driver, which comprises an external shell, a first fixing block is fixed at the corner inside the external shell, a gas guide hole is arranged at the position of the first fixing block close to the external shell, and a rotary driving piece is arranged at the bottom end inside a heat dissipation assembly through a fixing piece. A rotating shaft is movably mounted at the output end of the rotating driving part, a second fixing block is fixed outside the top end of the rotating shaft, and fan blades are fixed outside the second fixing block. The rotary driving piece rotates to drive the rotary shaft, the rotary shaft rotates to drive the second fixing block, and the second fixing block rotates to drive the fan blades, so that the fan blades discharge air which cannot dissipate heat in the outer shell through the holes in the first fixing block, and through the second air inlet holes formed in the two sides of the outer shell, the heat dissipation effici