Improvements in Electro Motors and Dynamos

23,418. Murray, T. B., and Johnson, G. Oct. 12. Dynamos and motors; armatures; field magnets.- An electromotor or dynamo is constructed with two armatures B, C, mounted on the same shaft, and each provided with one or more distinct windings connected to their respective commutators. By varying the connection of the armature windings from series to parallel, or vice versÔ, the speed of a motor may be varied. This may also be effected by varying the strength of the magnetic field. To obtain a sparkless commutation under such circumstances, a pair of smaller electromagnets G are arranged between the main magnets D, E, the additional magnets being preferably energized by coils in circuit with the armatures. The application of the invention to a multipolar machine is also described.