IMPROVING DEVICE FOR POWER-FACTOR OF ALTERNATING CURRENT ELECTRIC ROLLING STOCK

摘要

PURPOSE:To improve a power-factor by a pair of phase advancing circuits by mounting the phase advancing circuits consisting of capacitors and reactors only at the AC side of one rectifying circuit among a plurality of rectifying circuits. CONSTITUTION:The exchange voltage of a substation SS is applied to the primary winding N1 of a transformer Tr, and the voltage of secondary winding N21, N22 is each converted into DC by means of the rectifying circuits REC1, 2, cascade-connected and connected to a DC motor M1 for driving the electric rolling stock as load. The phase advancing circuit COC consisting of the reactor Lc and the capacitor Cc is connected to the secondary winding N22 in parallel with the rectifying circuit REC2. Here, impedance to a fundamental wave of the capacitor Cc is selected to value sufficiently larger than impedance to a fundamental wave of the reactor Lc. Accordingly, currents, which advance by pi/2 phase more than the primary voltage N1, flow through the phase advancing circuit COC through the transformer Tr, reactive currents generated from the rectifying circuits REC1, 2 are compensated and the power-factor can be improved.