Carbon brush and slip ring were important parts of the generator excitation system. Due to some factors, the phenomenon of carbon brush getting high temperature or wearing affected the safe generator operation seriously. The force of pressure spring was got on carbon brush by experiment, pressure values of both 8 positive carbon brush and 8 negative carbon brush in two generators were analyzed, the pressure spring pressure of two generators carbon brush was compared, reasons of brush getting high temperature were got , and proposals for change were given.

The geometric models and finite element models of triscrew extruder with different rotors have been established, and the models have been simulated by Polyflow. The mixing index, shear rate, logarithm of stretching, instantaneous efficiency, the average time efficiency and other evaluation parameters have been calculated using particle tracking method. The results show that, the number of shear and stretching in triscrew extruder in the same period increase with the increase of screw head numbers. Accordingly, the mixing effect is also increased gradually.