Dc motor controller in the course of long time use, may cause rust because of the influence of the external environment. Once appear, rusty spot that is very important for everyone, to do the maintenance work in time. Below we know about the causes of the motor controller rust spots. 1. Dc motor controller in the process of production, due to the plating time is not enough, the motor controller coating rust spots, this belongs to the technological process of the problem. 2. Before plating, because no surface dirt cleaning, check the motor controller can cause motor controller coating rust spots. 3. Because the device using the environment air liquidity is not good, humidity or temperature difference is bigger, also can cause motor controller coating rust spots. The above is the cause of rust spots dc motor controller, for that we need to handle efficiently according to these reasons.