STC generators are to be used in town, the countryside, worksites, mountain and pasture lands as a electric power source for lighting purpose. The generators are of three-phase four-wire type, making use of star connection with neutral point. The rated line voltage is 400V.phase voltage 230V.frequency 50hz.power factor 0.8(lag).It can provide 60Hz and the other voltage’ generator according to necessary. They can be coupled with a prime mover directly or through V-belt making right or reverse continuous rotation at the rated speed. when the revolution slip of prime mover is 3 and load varies in the range of 0-100 cos 1.0-0.8 they give food constant voltage. After sudden change (increase or decrease)of load. the generators will soon return to their normal working state. without any starting devices the generator can directly start an unloaded mouse cage type of induction motor.