This paper introduced a quality requirement of the flameproof hole on the enclosure of our works' 300A and 315A mining flameproof vacuum electromagnetic starter,and the focal point is technical treatment of flameproof hole,analyzed the reason of the quality issun of ream machining flameproof hole of ten occuring,put forward the corresponding solution.

Heat dissipation of the flame-proof and intrinsically safe frequency converter

The paper introduces chiefly the development of manufac turing dry-type flame-proof transformer with epoxy casting.

A new kind of explosion-proof soft starter used for mining is develop.

In accordance with the reform and practice of the governing system of explosion-proof and nature-safe model all-digital frequency conversion winch, introduces the principle and character of the application of AFE technology in achieving frequency converter movement in four quadrants.

In terms of gap tests of TNT and JH-2, they were approximatively achieved that were gap distances on the conditions of air and polyurethane foam by qualitative analysis, and conclusion was that copper liner effects on gap distance when applied conditi.

That brings some new subject to power electronic and electric drive,for example,research on explosion suppression induction motor design,analysis and research on temperature field with supplying by transducer.