The improvement plan, work principles and reform result on electric control system of main shafthoist in Linhuan Coal Mine are introduced, and the result is fine.
介绍了临涣煤矿主井提升机电控系统的改造方案、工作原理及改造效果，经过改造后的电控系统效果良好。
2
Practice has certified that various functions of the sys-tem achieve design requirements, and greatly improve the level of running and managing of service shafthoist system.
实践证明，系统各项功能均达到设计要求，极大地提高了副井提升系统的运行管理水平。
3
Wound-rotor induction motors that adjust speed by connecting resistors in series to rotor circuit have been easily found in the electrically controlled systems of shafthoist.