The product is a new type of driving device for various fixed belt conveyors, bucket elevator, winch, etc. The internal planetary cycloid reducer is used to make the exposed motor directly connected with the drum. That has the advantages of large bearing capacity, strong overload capacity, stable transmission, low noise, long service life, convenient use and maintenance, safe and reliable operation, etc. It can meet various requirements of backstop and coating. The explosion-proof signs of the explosion-proof external electric roller are dI, dIIAT4 and dIIBT4. DI is suitable for the coal mine with methane or coal dust, dIIAT4 is suitable for the place with T2 ~ T4 explosive dangerous mixture of I, IIA, IIb grade.