. The Street railway journal . I ) 1 1 1 1 ifoj 1 1 J 1 l II I I I I |Vw/| 1 1 1 1 1 1 r DIAGRAM OF TESTING INSTRUMENT feet satisfaction and quick results. The instrument will with-stand rough usage and is not influenced by stray magneticfields, is self-contained and does not require another field wind-ing for comparison. The reading attained on the scale of thisinstrument is direct and not in any technical term, but is simplya means for identification. The instrument may be connected into a regulation five-light550-volt lamp circuit in car or shop by a flexible cord and alamp plug. If no
. The Street railway journal . I ) 1 1 1 1 ifoj 1 1 J 1 l II I I I I |Vw/| 1 1 1 1 1 1 r DIAGRAM OF TESTING INSTRUMENT feet satisfaction and quick results. The instrument will with-stand rough usage and is not influenced by stray magneticfields, is self-contained and does not require another field wind-ing for comparison. The reading attained on the scale of thisinstrument is direct and not in any technical term, but is simplya means for identification. The instrument may be connected into a regulation five-light550-volt lamp circuit in car or shop by a flexible cord and alamp plug. If no light circuit is available, two dry batterieswill do. When the receiver is placed to the ear a loud pulsatingsound will be heard, but upon connecting a field winding to thebinding posts J and K and the switch E on the contact D, the. i FIELD TESTING INSTRUMENT sound will moderate to a certain intensity and remain pointer is now moved along the scale until a point isreached where the sound will perfectly balance—that is, therewill be no variation in intensity when the switch E is alter-nately shifted into connection with the contacts C and D. If the field winding is new and in standard condition, thereading attained will be the value of this type of field may be obtained in this manner of any number ofdifferent types of fields. If, when testing other field windings,the sound in the receiver is not as loud on contact D as on C,when the pointer is set to standard reading on the scale, thefield is short-circuited. To find the degree of short circuit thepointer is moved down the scale until the sound again balanceson both sides of the switch C and D. The reading thus ob- tained will be the proportion of short circuit in the field wind-ing. To test coils of higher resistance the range of
Size: 1864px × 1340px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
