As we all know, no matter what kind of motor control for a long time, will be hot. Brushless motor controller is not exceptional also, brushless motor controller fever reason mainly has: (1)Generator controller overload, make the load current, voltage does not exceed the rating. (2)The load power factor is too low, adjust the load, the excitation current shall not exceed the rating, (3)Speed is too low, adjust the speed to the rating. (4)Generator controller is part of a winding short circuit, and find out short circuit, correct or replace the coil. (5)Downwind obstruction, eliminate obstacles, open motor controller, thoroughly air duct. Motor controller load the runtime controller with power loss, will eventually be into heat energy, it can make the motor controller temperature, more than the ambient temperature. The value of the motor controller temperature higher than the environment temperature is called heat up. Once the warming, motor controller will be around to heat dissipation; When the heat emitted by motor controller unit time is equal to the heat generated by the, motor controller temperature no longer increases, and maintained a stable temperature, which is in a state of thermal equilibrium.