Shipbuilding and Shipping Record . Fig. 3.—Hopkinson-Thring Torsionmeter. Hamburg. The beam projected on to the scale by the fixed mirroris taken as the zero point, whilst the beam projected by the movablemirror indicates the amoimt of torque on the shaft. Both mirrorsrotate with the shaft, but even at moderate speeds the reflectionsappear as continuous fines of light across the scale. Fig. 4, and thereis thus no difficulty in taking the readings. Tlie fixecFnurror isattached to the flange on the first collar referred to above, and themovable one is attached to the flange carried by the sleeve
Shipbuilding and Shipping Record . Fig. 3.—Hopkinson-Thring Torsionmeter. Hamburg. The beam projected on to the scale by the fixed mirroris taken as the zero point, whilst the beam projected by the movablemirror indicates the amoimt of torque on the shaft. Both mirrorsrotate with the shaft, but even at moderate speeds the reflectionsappear as continuous fines of light across the scale. Fig. 4, and thereis thus no difficulty in taking the readings. Tlie fixecFnurror isattached to the flange on the first collar referred to above, and themovable one is attached to the flange carried by the sleeve. Thefixed mirror is adjusted so that the beam of hght reflected from itis received at the same point on the scale as that from the movable. Fig. 4.—Indicator for Hopkinson-Thring Torsionmeter. mirror when there is no torque on the shaft. If theposition of theapparatus becomes altered relatively to the scale owing to thewarming up of the shaft or from other causes, tliis is indicatedimmechately to the observer by an alteration in the position of thezero as reflected by the fixed mirror. Hence the scale zero may beadjusted, if desired, by moving the scale so that its zero coincideswith the reflection from the fixed mirror, but this is not necessaryto obtain a correct result, since the mean of the two readings milbe the same. The constant of the instrument, viz., the factor wliichwhen mul-tiplied into the product of the torsionmeter reading and the revolu-tions per minute gives the horse-power may be determined^eitherby calculation or by experiment. It is determined by^calculationfiom the various quantities given in formula (iii) above, modifiedif necessary in the case of a hollow shaft, together with a factor 62 SHIPBUILD
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondon, bookyear191
