Abstract: In this paper,theoretical aspects and a practical scheme of new speed regulating system have been presented based on a forced commutation principle.Experiments on cascade speed-regulating devices of slip ring nonsynchronous motors,and on speed-regulating devices of D.C.motors demonstrate that power factor may reach 0.9 and higher,or,in some cases,the capacitive reactive power may be generated to compensate the power supply for the inductive reactive power.Control systems of this kind are simple in design and may be found wide use in drive mechanisms of pumps,fans and other similar equipment where greater factor and more efficiency are desired.