QUADRATURE-AXIS REACTANCE DROP COMPENSATED THREE-PHASE SYNCHRONOUS MACHINE

摘要

PURPOSE:To economically obtain a synchronous motor having sufficiently great maximum output without increasing a short circuit ratio, by arranging a horizontal shaft field winding beside a direct shaft field winding, and by feeding the DC exciting current of polarity for generating a magnetomotive force to cancel a magnetomotive force due to motor current horizontal shaft component, to the windings. CONSTITUTION:By DC exciting current If flowing through a direct shaft field winding 6, main magnetic flux crossed over armature windings 2-4 is generated, and then, on the armature windings 2-4, non-load induced electromotive force Eo is generated. Besides, by DC exciting current Ig flowing through a horizontal field winding 6, a magnetomotive force in the direction of cancelling a magnetomotive force due to armature current horizontal shaft component is generated. The output of a salient pole type three-phase synchronous machine is set as shown in an equation. Through the equation, if the compensation rate k of quadrature axis reactance drop is set to be approx. 1, the coefficient of sin 2 delta on a second term on the right is remarkably increased, and as its result, remarkably great maximum output is obtained. As a result, the value of the maximum output is not so much influenced by a fact as to whether a short circuit ratio is large or small.