Apparatus for the determination of the magnetic properties of short bars . Fig. I.—Photograph of magnetic comparator. Fisclier] Magnetic Testing of Short Bars. 515 and these dimensions were retained for use in the final form of theapparatus. 2. APPARATUS. Figure I is a photograph of the comparator showing the essentialfeatures of its construction. It consists, primarily, of an electro-magnet with pole pieces and yoke of Norway iron and a magnetiz-ing solenoid of approximately 1,200 turns of No. 17 copper wiresurrounding the yoke. Symmetrically located in the ends of thepoles are two 6 mm holes
Apparatus for the determination of the magnetic properties of short bars . Fig. I.—Photograph of magnetic comparator. Fisclier] Magnetic Testing of Short Bars. 515 and these dimensions were retained for use in the final form of theapparatus. 2. APPARATUS. Figure I is a photograph of the comparator showing the essentialfeatures of its construction. It consists, primarily, of an electro-magnet with pole pieces and yoke of Norway iron and a magnetiz-ing solenoid of approximately 1,200 turns of No. 17 copper wiresurrounding the yoke. Symmetrically located in the ends of thepoles are two 6 mm holes with centers 12 mm apart in which theknown bar and the bar to be tested are lightly clamped by means of. Fig. 2.—Diagram of electrical circuits and connections. the thumbscrews. Coaxial with these holes and held in positionbetween the poles are two test coils of 100 turns each, wound onbrass forms of a slightly larger internal diameter than the diameterof the bars which they surround. In the photograph is shown atest bar 35 cm long projecting equal distances beyond the sides ofthe poles. The other bar is 10 cm long, and consequently does notproject beyond the sides of the apparatus. The approximate sizeof the apparatus may be judged from a comparison with the testbar. The electrical connections are shown in Figure 2. Each of thetest coils can be separately connected to the ballistic galvanometer 5i6 Scientific Papers of the Bureau of Statidards. [ through the secondary of the calibrating mutual inductance. Thegalvanometer is calibrated in the usual way by reversing the propercurrent through the primary of the mutual inductance and adjust-ing the sensitivity by means of resistance
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Keywords: ., bookcentury1900, bookdecade1920, bookidapparatusfor, bookyear1922
