Elements of Direct Current Electrical Engineering

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 edition. Excerpt: ... connections. Imagine the armature to consist of a cylinder of cardboard, and to be cut along a line parallel to the axis, and folded out flat, or developed, as it is called. We then obtain a view somewhat as shown in Fig. 66, where the unshaded portions represent the slots. Suppose now we connect the end of a conductor (a) under a north pole to the end of a conductor (b) under a south pole (see Fig. 67), we get an addition of E.M.F.'s. Let these conductors be a distance apart equal to. the polar pitch (distance from mid-point of one pole to mid-point of the next measured round the armature). Let now the other end of (6) be connected to a conductor (c) next to (a)--either just before it or just Fig. 68.--Method Of Forming "Lap" Winding after it. Connect the other end of (c) to the conductor (d) next to (ft) a pole pitch away. (See Fig. 68.) Proceeding thus we obtain what is known as a lap winding. The number of conductors is so chosen that, after proceeding all round the armature, we come back to the other end of the conductor (a) from which we started. It should be noted that, if (a) and (c) are upper conductors, (b) and (d) will be lower ones, and vice versa. This is because the end connections may be Fig. 69.--Method Of Forming "Wave" Winding made more easily than if they were all on the same level. The point X in Fig. 68 is joined to the commutator segment corresponding to conductors (6) and (c). 7. Wave Winding.--In this, the joint between (a) and (b) is made exactly as before, but, instead of coming back to the conductor next to (a), we proceed to the one under the next pole, a pole pitch away, as shown in Fig. 69. The number of conductors is so arranged that, after proceeding once round the armature, we...