PLAN OF THE UNI-DIRECTION DYNAMO
About four ounces should be enough for this armature, and the ends are to be passed through small holes in the brass end (B); see [Fig. 11]. One end must be soldered to one commutator, the other end to the other commutator. The end-piece (B) is attached to the iron armature (A) with machine-screws; then C is to be made fast in a similar manner.
When putting the parts together, it would be well to use some shellac on the wooden cylinder and driving-wheel to make them hold to the shaft.
By following the plan in [Fig. 10], it will be an easy matter to put the parts together; when they are assembled the complete machine will appear as shown in the drawing ([Fig. 12]).
The driving-wheel should be of wood five-eighths of an inch thick and six inches in diameter, and held in the frame of wood and metal brackets by a bolt. A short handle can be arranged with which to turn the wheel, and a small leather belt will transmit the power to the small wheel on the armature shaft. As the armature is revolved the lines of force are cut and the current is carried out through the wire attached to the binding-posts on the blocks (G G).
Considerable current may be generated if the armature is driven at higher speed than the hand-wheel will cause it to revolve. This can be accomplished by running the belt over a larger wheel, such as the fly-wheel of a sewing-machine, or connecting it to a large pulley on a water-motor. The latter may be attached to a faucet in the wash-tub if there is pressure enough to do the work.