Apart from terms mentioned earlier, the subsequent terminology desires discussion:
Back pitch (YB): It's the gap measured in terms of armature winding amongst the 2 sides of a coil at the back of the armature shown in the fig. It’s represented by YB. For instance, if a coil is made by connecting conductor one (higher conductor in a slot) to conductor twelve (bottom conductor in another slot) at the back of the coil, then back pitch is YB=12-1=11 conductors.
Front pitch (YF): It is the gap measured in terms of armature winding between the coil sides hooked up to anyone commutator segment shown in the fig. it's denoted by YF. For instance, if coil side twelve and coil side three are connected to an equivalent commutator segments, then front pitch is YF=12-3=9 conductors.
Resultant pitch (YR): It is distance (i.e. measured in terms of armature conductors) between one conductor and the opening of successive conductor to that it's connected shown in fig. It is denoted by YR. Therefore, the resultant pitch is that the pure mathematics add of the back and front pitches.
Commutator pitch (YC): It's the quantity of commutator segments spanned by every coil of the armature winding.
For lap winding, YC=1
For wave winding, YC=1 pole pitches (segment)
Progressive winding: A progressive winding is one within which, collectively traces through the winding, the connections to the commutator can progress round the machine within the same direction as is being traced on the trail of every individual coil.
In fig(a) shows progressive lap winding. Note that
YB>YF and YC= +1.
YB>YF and YC= +1.
Retrogressive winding: A retrograde winding is one within which, collectively traces through the winding, the connections to the commutator can progress round the machine within the other way to it that is being traced on the trail of every individual coil.
In fig(b) shows retrogressive lap winding. Note that YF>YB and YC= -1. A retrograde winding is infrequently used as a consequence of it wants a lot of copper.