Dc motor controller in use of long time, due to the influence of the external environment rusty happens. Once a rusty spot you will need to attach importance to, and do the maintenance work in time, avoid aggravating corrosion. Below small make up to say about the cause of dc motor controller rusty spot. 1. Due to the production process, there is no enough time to do plating, so it coating rust spots. 2. Before electroplating, failed to clear dirt on the surface of the dc motor controller in a timely manner, can also lead to coating rust spots. 3. In use, because of poor liquidity environment air, humidity or temperature difference is bigger, can also lead to coating rust spots. 4. If the packing sealing failure of dc motor controller, oxidation caused it to happen, thus coating rust spots. Above is the cause of the rust spots, dc motor controller in use should pay attention to and do maintenance work.