1905-1970's ; motor-generator sets for converting alternating current to direct current (1930) ; 1930 unique photos of factory settings ; direct current motors ; tracer drive to control path of tool to automatically duplicate outline of template ; gearmotors and unibrakes ; induction motors ; adjustable speed motor ; electric speed indicator ; tool drilling machines ; Programmed Numerical Control ; industrial power transmission ; "AutoMage" programmable controller ; air conditioning units ; engineering services ; pulse-width modulated inverter ; mechanical, electrical and mining repair services ;