New or improved instructional device for facilitating explanation of the construction and winding of electric armatures and demonstration of the effects of wrong connections and errors in manufacture

摘要

179,081. Brook, C. B. May 13, 1921. Teaching electricity.-A device is provided for demonstrating the construction and winding of electric armatures and the effects of short-circuits &c. The device comprises a flat disc d rotatably mounted upon a fixed spindle c attached to a brush-rocker device e of insulating-material, provided with radially extending arms having contact plates upon their underside to represent brushes, which bear against metallic blocks f on the rotating disc acting as commutator segments to carry current to covered flexible wires i, i1 connected to the terminals of lamp-holders h around the circumference of the disc. The flexible wires are held by two circumferentially spaced series of clips g, g1, the two series being at a suitable distance apart in radial alignment and representing the slots of a plate of a drum armature. The wires are preferably of different colours to represent the two portions of a coil passing through each slot, and are provided with removable plugs fitting into sockets in the commutator blocks to illustrate different methods of winding. The contact blocks of the brush-rocker device are provided with means of cross connection by short wires k, and with wires l leading to a source of electrical supply. The spindle is fixed upon a board or plate a having representations of pole-pieces painted or otherwise applied in the requisite positions.. A switch m can be mounted on the board and included in the supply circuit. In a modification the device is constructed to represent a motor or generator, having the wires representing the coils disposed within the armature slots and connected to lamp-holders on a disc supported on the armature shaft at the end remote from the commutator.