| 摘要 |
1499449 Control of D.C. motors PHILIPS GLOEILAMPENFABRIEKEN NV 12 Dec 1975 [17 Dec 1974] 51002/75 Heading H2J The drum of a washing and spin drying machine is driven with a fixed speed transmission ratio by a D.C. motor M, which is fed from an A.C. supply K1, K2 through a first rectifier bridge of diodes D1, D2 and thyristors TH1, TH2, whose firing angles are controlled to provide voltages producing low and medium speeds of the motor, Fig. 2 (not shown), the speed being increased, at least during the final spin drying stage of the machine cycle, by operation of switches S1, S2 by the programme timer to supply the motor through a second rectifier bridge of diodes D1, D2, D4, D5 and capacitors C1, C2, which charge during the first part of each bridge rectified half cycle and discharge through the motor during the remaining part to produce a voltage doubling effect, Fig. 3 (not shown). The two bridges may be independent of one another and storage components other than capacitors may be used. |
