GB190712495A - Improvements in Dynamometers and Power Indicators. - Google Patents

Abstract

12,495. Barr, A., and Stroud, W. May 30. Dynamometers.-Relates to electric apparatus for ascertaining the relative torsion between two sections of a shaft transmitting torque, of the type in which intermittent make-and-break arrangements at the two sections are employed to modify the current in a circuit containing either a constant source of current or a generator driven by the shaft ; in the latter case, a measure of the product of the speed and torsion is obtained. In the arrangement shown in Fig. 1, two metal disks R1, R2 with regularlyspaced insulating-blocks are placed on the sbaft, which is earthed. One pole of the battery D is earthed and is also connected through one winding of the moving coil of a galvanometer G to one of the brushes B2 bearing on the metal disks, the other brush B1 being connected to the other pole of the battery. The other winding of the coil is in circuit with the battery and an adjustable resistance E, whereby a zero reading may be obtained. Alternatively the brushes may be arranged in parallel. Various other methods of measuring the current due to relative displacements of the disks may be employed. In one arrangement, the two windings are in coils fixed relatively at rightangles, whereby a deflexion reading is obtained; in others, the coils C1, C2 with planes mutually at right - angles are arranged the one above the other, the magnetic field being formed by permanent magnets M1, M2 or M, M<1>, placed as shown in Figs. 3 and 4. The brushes may take the form of pivoted inverted L-shaped pieces normally retracted from the disks by springs, but capable of being operated by an electro magnet.