| 摘要 |
<p>1,058,856. Control of A.C. motors. GENERAL ELECTRIC CO. June 26, 1964 [July 3, 1963], No. 26668/64. Headings H2H and H2J. [Also in Divisions G3 and H3] A circuit controlling the power in an A.C. load M, comprises for each phase a controlled rectifier 11 fired by pulses from a transformer winding 19 at a point in the cycle when a saturable reactor 17, 25 saturates, this point being determined by the current in control windings 25 whch are commoned through diodes 29 to a, transistor 33 which equalizes the currents through the windings 25 so that each rectifier 11 &c. fires at the same retardation. In a single phase circuit two rectifiers 11, 12 are utilized with opposite polarity diodes 13, 14 to carry the reverse current. Alternatively, the rectifiers 11, 12 may be connected in reverse parallel. In another arrangement (Fig. 9, not shown), the windings 19 may be omitted and anode firing employed by connecting the anode of rectifier 21 to the anode of rectifier 11 &c. The load M may be a motor whose speed is controlled through a shaft driven tachometer, the output of which is compared with a reference signal R, the error from which is applied to a transistor 35 controlling the transistor 33. In an alternative arrangement, the diodes 13 are replaced by controlled rectifiers (Fig. 8, not shown). A twophase arrangement is given in the Specification.</p> |
