1, submersible pump pumping mud, the medium density caused by overload. The measured medium density is greater than 1.3, or even reach 1.5 ~ 1.6; and motor power richness coefficient is small (generally 1.05 ~ 1.2). 2, the siltation of the sediment in the pump body, the impeller is overloaded caused by braking, the motor is almost blocked state of operation. 3, the rotor shaft hole clearance and the gap between the impeller mouth ring is filled with sand so that the shaft brake caused overload. 4, individual manufacturers in order to win the pressure in the competition, artificially reduce the motor power. 5, the lack of legal norms, the industry's mining submersible motors anti-overload measurement standards, so that the lack of market competition standard point. This article Keywords: Submersible pumps