At that time, Yang Hongjun invented the brushless excitation motor, but due to the harsh prison environment, the experimental equipment provided to him was relatively backward and the manpower was insufficient (the prison staff did not believe that he could invent something useful, thinking that he just wanted to take advantage of the law to avoid the death penalty), which was basically equivalent to Yang Hongjun's own works, which led to the poor practicability of the brushless excitation motor he invented. Up to now, it has not been put into mass production, and China is still using the brushless motor technology provided by Mitsubishi.
The prison prevention and control system invented by Yang Hongjun 20 14 is very practical (this product can escape from prison during the crackdown period ... the level is here).