Rolling armature

(a) An armature for a permanent horseshoe magnet consisting of a straight cylinder of soft iron on which a heavy wheel is mounted. When the legs of the magnet are inclined downward and the bar is laid across them it rolls down to the poles, across their ends, and back up the under side. It is merely a magnetic toy or illustrative experiment.

Synonym: Wheel Armature.

(b) Another form consists of little bars of iron with brass discs attached to the ends. On placing two of these together and bringing the poles of a magnet near them, as shown, they become magnetized with like polarity by induction and repel each other, rolling away in opposite directions.

Fig. 30. ROLLING OR WHEEL ARMATURE.

Fig. 31. ROLLING ARMATURES.