Armature Trouble in Electric Coal Cutting Machine in a Colliery

After receiving a report from a Colliery that a 50 H.P. Coal Cutting Machine Armature has broken down I arrived on the spot and after examination found that the Commutator Segments in the armature had spread out and the Brushes all smashed. The armature therefore had to be brought up to the surface for necessary repairs. As the machine had to be started quickly and as the repairs to the armature would take time, I went to a Sister Colliery under the same management and, seeing the Officer-in-Charge there. I found that there were three armatures there, two fitted to the machine and one packed in a box (a spare one which was supposed to have been repaired in Calcutta).