"DC Fan" facts, the age of the system due to insufficient cooling system is reduced, so the design engineer should understand that sales and price system, probably because life does not match the user's system is expected to decline. And the fan in use, the following are also prone to failure, just as we explain today, so that we can promptly check vane cracks or breaks in daily use. This phenomenon often occurs in large power plants, the most serious or even impeller coaster accident; motor failure. Such as over-current, severe burn out the motor; blade wear. Mainly it occurred in the induced draft fan.