| 摘要 |
1,262,504. Electric motors. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 28 Feb., 1969 [29 Feb., 1968], No. 10985/69. Heading H2A. An electric motor including a plurality of energizing windings has a control circuit comprising a plurality of inputs for connection to rotor position sensing apparatus, the inputs being connected to respective transistors controlling the energization of the windings and having a common emitter impedance. In the arrangement shown a coil 19 supplied from a high frequency oscillator 25 is mounted on a magnetic core 18 rotatable with the motor rotor 14 and comprising an arcuate portion 18b so that a voltage of oscillator frequency modulated by a frequency dependent on rotor speed, Figs. 3A, 3B, 3C (not shown), is induced in three position sensing coils 21, 22, 23. The induced voltages are rectified by diodes 44, 45, 46 and fed to transistor pairs 54 and 60, 55 and 61, 56 and 62 energizing the stator windings 11, 12, 13. The common emitter impedance 57 ensures that when one transistor 54, 55 and 56 is conducting the other two are kept in the OFF condition. In a modification, Fig. 2 (not shown), the outputs of coils 21, 22, 23 are fed directly to the transistors, the rectification of the induced voltages being effected by the transistors themselves. |
