METHOD FOR CONTROL OVER ROTATIONAL SPEED OF M-PHASE ELECTRIC MOTOR AND DEVICE FOR ITS IMPLEMENTATION (VERSIONS) Russian patent published in 1998 - IPC

FIELD: electrical engineering. SUBSTANCE: method is meant for adjustment of rotational speed of m-phase electric motor. According to the method of control over m-phase, asynchronous motor windings of its stator are connected through regulators of voltage amplitude to network having voltage V_o and frequency ω. At moment of switching over of windings of stator phases of currents in windings are shifted simultaneously with speed determined from expression ±ψ = n - ω and momentary value of voltage in connected winding of stator is changed by law U_m = 2U_osin(ωt - 2πm/3)cos(ψt ∓ 2πm/3),, where n is rotational speed of motor; ψ is speed of shifting of phases of currents in windings of stator; V_m is momentary value of voltage fed to windings of stator; ω is frequency of voltage of supply network. EFFECT: improved efficiency. 4 cl, 6 dwg