. Electric railway gazette . d while amply able to carry half anampere for lights may easily fail to carry 20 ormore amperes for the necessary power. This accident isvery liable to happen where flat rails on wooden beamsare used. These rails are frequently unbonded or thebonds have broken loose. Hence, when a motor getsupon such a rail and stops it is frequently stalled. 2d. The car persists in moving with the controller fulloff. This usually occurs while the car is in motion andan attempt to stop is made. When it is discovered thatthe car is no longer under control, open the overheadswitch an
. Electric railway gazette . d while amply able to carry half anampere for lights may easily fail to carry 20 ormore amperes for the necessary power. This accident isvery liable to happen where flat rails on wooden beamsare used. These rails are frequently unbonded or thebonds have broken loose. Hence, when a motor getsupon such a rail and stops it is frequently stalled. 2d. The car persists in moving with the controller fulloff. This usually occurs while the car is in motion andan attempt to stop is made. When it is discovered thatthe car is no longer under control, open the overheadswitch and bring the car up with the break. This diffi-culty usually has its cause in the controller itself. Re-move the cover from the controller and throw on theoverhead switch. The defective portion will usuallyindicate its whereabouts by a smoke. Thus the causemay be detected and removed. Sometimes the troublelies in two or more crossed wires in contact under thecar. This may be detected as indicated in the case ofthe FIG. 50. In this difficulty current is finding a path throughthe motors when it should not do so. It is thereforebridging some insulation, and the chances are smokingand destroying it. 3d. The motors get hot in parts. There are several partsto a railway motor that are liable to heat and for differ-ent reasons. The bearings may heat for lack of oil, orfor no lack of sand or grit. They may be out of lineor the shaft may be sprung. The last two causes are not usual, and for them there is no ready remedy. The first two are common causes,and should be remedied by profuse lubrication. The commutator may heat because of its proximity toa hot bearing, but is more liable to heat because ofsparking of the brushes. This cause requires a wholesection to treat of, and will be discussed later. Some-times the heat is due to needlessly heavy pressure of thebrushes on the commutator. Examine the motor inmotion, and if it be sparkless, relieve the brush pres-sure. If there
Size: 2109px × 1185px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1895
