Commutation and Current Collection in Hydrogen

This paper describes a number of tests on commutator machines and slip-rings operating in hydrogen. The results seem to warrant the following conclusions: (1) A commutator machine designed and adjusted for good commutation in air will operate satisfactorily and give good brush life in hydrogen. (2) If a commutator machine mutst spark in hydrogen, the brush life may be increased many times by keeping the relative humidity below, ten per cent. (3) The contact resistance of carbon brushes on a commutator may be lowered materially by the introduction of hydrogen. (4) Carbon or graphite brushes cannot be operated satisfactorily on plain tool-steel slip-rings running in hydrogen, and (5) The contact drop between a carbon or graphite brush and a brass slip-ring may be ten times as high when the ring is ruinning in air as when it is running in hydrogen.