. Testing electrical railway bonds . not changed. in tnis way the bondresistance co^ld be obtained, regardless of the value of the cur-rent in the rail. The action of the needle was quick enougnto indicate all bad bonds at a high rate of speed, even thothey were bad at successive joints. These brushes worked fairly well, mechanically, on smoothtrack and at slow speeds. Y/hen moving at a faster rate, how-ever, the brusnes would gradually work down under the angle ironsand ohen when some slight inequality of the track was passed 6 woula be bent, after whichthey had. no pressure on the
. Testing electrical railway bonds . not changed. in tnis way the bondresistance co^ld be obtained, regardless of the value of the cur-rent in the rail. The action of the needle was quick enougnto indicate all bad bonds at a high rate of speed, even thothey were bad at successive joints. These brushes worked fairly well, mechanically, on smoothtrack and at slow speeds. Y/hen moving at a faster rate, how-ever, the brusnes would gradually work down under the angle ironsand ohen when some slight inequality of the track was passed 6 woula be bent, after whichthey had. no pressure on the adjustable pieces, M (Figs. 5 and 6) were placed on theends of the angle irons to hold the brushes in a more verticalposition. The piece ii was also doubled for strength, but theapparatus was still too wean to withstand tne sixock at railroadcrossings. furthermore there were so many small pieces, and screws, that a number of parts would be lost each trip. becauseof this unreliability, the design was changed to that snown in F I G 7. Pig. ?. The pieces, M, were discarded, and the lower ends ofthe angle irons bent closer together. The spring brushes were replaced by a 5/6 mild steel straps, K. This brusn was moresensitive, electrically, than the clock spring, tuo dif-ficultywas again experienced in urcs^mg raiiroaus. ihe brush itselfwas strong enough, but the blow would bend the angle brushes could not be held together long enough to checkany former readings, and the entire apparatus was finally discard. ed. The apparatus as next constructed, is indicated in Fig. pieces of wooa fibre, x, were boltea to each end of theframe of one trunk, in ohe plane of the wheels. A spring, S, 7 F I G 8
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