| 摘要 |
950,842. Transducers. PHILIPS ELECTRICAL INDUSTRIES Ltd. March 16, 1960 [March 19, 1959], No. 9285/60. Heading H4J. In a balanced armature transducer any unbalance in the magnetic system resulting in flux flowing in the armature in the rest condition is removed by providing a high-reluctance shunt to at least one air gap so as to reduce the armature flux to zero. In each of the transducers of Figs. 1 and 2 a permanent magnet 1 surrounded by a winding 12 has soft iron polepieces 2, 3 with extensions 14, 15, between the free ends of which is a soft iron armature 4, one end of which is clamped in the base-plate of a U-shaped soft iron yoke 5. If an alternating current is applied to the winding 12, any unbalance will result in the induction of an alternating voltage in the coil 10 surrounding the armature 4 which will be indicated on the meter 11. The transducer may be balanced by applying to one of the two limbs of the yoke 5 one or more layers 13a (Fig. 1) of a cement, laquer, or glue, which has been made mag netically conductive by adding, for example, carbonyl iron powder. Alternatively, a magnetically conductive strip 13b (Fig. 2) may be provided at a distance from the limb concerned. In a modification, flexible magnetically conductive strips or wires (not shown) may be secured one to each of the limbs of the yoke 5 or one to each of the extensions 14, 15, the distance of one of these strips or wires from the limb on the other side of the air gap being varied until a balance is established. |
