| 摘要 |
754,474. Electric measuring systems. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. April 7, 1954 [April 18, 1953], No. 10171/54. Class 40(1) [Also in Group XXXVI] A pick-up device for determining the stress in a magnetic member comprises a U-shaped core (Fig. 1) with A.C. energized coils 2 on the limbs and a similar core 3 with pick-up coils 4 on its limbs located symmetrically with respect to coils 2, the unit being placed on or near the surface of the member to be tested so that with no stress the pick-up voltages in coils 4 are equal and opposite, but with a stress in the member the magnetic lines of force are distorted and a resultant voltage is obtained from coils 4. If the magnetic test member is not isotropic zero adjustment may be effected by introducing an auxiliary voltage, or by rotating one coil unit relative to the other. In one circuit arrangement (Fig. 5) the resultant voltage in coils 4 is compared in rectifiers 16 with the magnetizing voltage, so that a meter 9 indicates the magnitude and direction of the stress in the test body- The apparatus may be used to determine the weight of a load by determining the stress in a link of the supporting member. |
