What is an Armature Winding, and Its Types

Generally, an armature winding is like a conductor, and it covers with a single cotton cover, double cotton cover, otherwise cotton fiberglass and enamel. Usually, the rolls of the armature winding will bound mutually with the cotton tape. Thus the coils will be dipped in soaked varnish then dried up. The armature winding is defined as the conductors which are housed and protected within the armature slots are connected properly. These windings are arranged in the armature slots. The helpful e.m.f will be encouraged in this winding which is received across the brushes. This article discusses what is an armature winding, and its types.

What is an Armature Winding?

Armature winding can be defined as, an electrical machine in which emf can be generated because of the air gap field flux. It must be noted that the air gap is produced because of the DC current flow in the winding. In general, this winding is housed on slots of the stator &  the field winding on rotor slots. The dc motor armature winding diagram is shown below.

Generally, this is housed on stator slots and field winding on rotor slots to machine synchronous. This winding is placed in the slots of a rotor whereas the field winding is placed in slots of the stator. The designing of the armature winding can be done using the copper, & includes the huge number of insulated coils. These two coils may  have several turns and may be connected either in series otherwise parallel based on the required type of winding

Types of Armature Winding

Generally, the armature winding in dc machine is wound by using two techniques and these are also known as types of an armature winding such as Lap Winding and Wave Winding.

 a). Lap Winding

In this type of winding, the connection of the conductors is done in such a way that their parallel poles & lanes are similar. The last part of every armature coil can be connected toward the nearby section on the commutator. The digit of brushes in this winding can be similar toward the digit of parallel lanes, & these brushes are separated evenly into positive as well as negative polarity winding. The applications of lap winding mainly include high-current, low voltage machines. lap windings are classified into three types which include the following.

• Simplex Type Lap Winding
• Duplex Type Lap Winding
• Triplex Type TLap Winding

 1). Simplex Type Lap Winding

In this kind of winding, the ending of one coil is connected to the commutator section as well as the beginning end of the secondary coil can be arranged under a similar pole, and also the digit of parallel lanes is equal to the digit of poles of the windings.

 2). Duplex Type Lap Winding

In this type of winding, the digit of parallel lanes among the pole is double the digit of poles. The applications of lap winding mainly involve in huge current applications. Such kind of winding is obtained by arranging the two same windings on the similar armature as well as linking the even number commutator bars toward the primary winding & the off number to the secondary winding.

 3). Triplex Type Lap Winding

In this type of winding, the windings are associated with the 1/3rd of the bars of the commutator. This lap winding has several lanes as well as therefore the applications of triplex type lap winding mainly involve in huge current applications. the main drawback of this winding is that it uses several conductors which will enhance the winding cost.

b).Wave Winding

In this kind of wave winding, there are only two parallel lanes among the positive as well as negative brushes. The final end of the first armature coil is linked with the beginning end of the second armature coil commutator segment at some distance. In this kind of winding, the conductors are associated with the two parallel lanes of the machine poles. The digit of parallel ports is equivalent to the digit of brushes. This kind of winding is applicable for low-current, high-voltage machines.

Once it passing one round, then the armature winding drops into a slot toward the left side of its beginning point. So this type of winding is named as retrogressive windings. Similarly, once the windings of an armature drop on one slot toward the right then it is named as progressive winding.

Suppose the two winding layers & that the AB conductor must be at the higher layer semi of the slot on the right or left. Assume that the YF and YB are front and back pitches. The amounts of these pitches are nearly the same to the winding pole pitch. The the following equation gives the winding average pitch.

The following equation provides the winding’s standard pitch.

Y_A =Y_B + Y_F/2

If the whole no. of the conductor is ZA, then the normal pitch can be defined by the following equation

Y_A =Z+2/p or Y_A =Z-2/p

In the above equation, the number of poles can be denoted with ‘P’, and it is always even, so Z is always measured like an even digit Z = PY_A ± 2. Here, both the signs like + and – are used for progressive winding as well as retrogressive windings.

Thus, this is all about what is an armature, different types of armatures. From the above information finally, we can conclude that these windings are essential components in an electrical machine. It consists of a set of coils within the slots and consistently spaced around the armature margin. Here is a question for you, what is the difference between field winding and armature winding?

Image Credit: Nptel