. The street railway review . between fields and arma-tures in the T. H. or E. sjstem, or at the cut-out box, or con-troller on the Westinghouse or Wightman S3stems. Theformer has been shown in Figs. 9 and 10, while in Fig. 11the circuit is shown to meet not until having passed the fieldand armature of each motor. Having these simple circuits in our mind, we can easilyaccount for the action of a motor. Suppose that, during asevere rainstorm, the lower one of the field coils becomes sosoaked that the insulation first begins to smoke, then givesway to the current, which jumps across the last tur
. The street railway review . between fields and arma-tures in the T. H. or E. sjstem, or at the cut-out box, or con-troller on the Westinghouse or Wightman S3stems. Theformer has been shown in Figs. 9 and 10, while in Fig. 11the circuit is shown to meet not until having passed the fieldand armature of each motor. Having these simple circuits in our mind, we can easilyaccount for the action of a motor. Suppose that, during asevere rainstorm, the lower one of the field coils becomes sosoaked that the insulation first begins to smoke, then givesway to the current, which jumps across the last turns to thefield core. As soon as this takes place there is a hard kick orjerk, ^nd the car fuse melts. The fault that has developedhas caused an excess of current to flow through the field wind-i to the core, the armature having both brushes connectedto the motor frame, is short circuited, and rotates between thefield poles, which are far more powerful than when operatingnormally. The armature generates under these conditions. currents far greater than the wire on it is calculated for, orcould stand for any length of time. The quantity of electricalenergy developed by the armature can only be produced atthe expenditure of power, which, in this case, is supplied bythe momentum of the car, which quickly comes to a condition is shown in Fig. 12, which represents atrouble which frequently occurred on now abandoned motorconstructions. This figure clearly shows how the current,instead of following thg wire of the lower coil and going to 631 the brush thiougli armature; to brush, aiul then to ground, asin Fig. S, how it takes a short cut to the frame of the motor,and how, thereby, the armature is closed on itself, or shortcircuited. The path being indicated by arrows. If there isbut one motor on the car, it will not start up when the fuse isagain inserted, but the fuse will melt again. If there are twomotors, the car would not come to a standstill as ([uickly aswith a si
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Keywords: ., book, bookcentury1800, bookdecade1890, booksubjectstreetrailroads
