What is an Armature? Working with Diagram and Applications

The first armature was used by the magnet keepers in the 19th century. The related equipment parts are expressed in terms of an electrical as well as mechanical. Though definitely separate these two sets of terms are regularly used similarly which includes one electrical term as well as one mechanical term. This may be the reason for confusion whenever working with complex machines such as brushless alternators. In most of the generators, part of the rotor is the field magnet that will be active that means rotates, whereas part of the stator is armature that will be inactive. Both the generators as well as motors can be designed with an inactive armature & an active (rotating)  field otherwise an active armature as the inactive field. The shaft piece of a stable magnet otherwise electromagnet, as well as the moving iron piece of a solenoid, particularly if the latter performs as a switch or else relay, can be referred to as armatures. This article discusses an overview of the armature and its working with applications.

What is an Armature?

An armature can be defined as an power generating component in an electric machine where the armature can be a rotating part otherwise a stationary part in the machine. The interaction of the armature with the magnetic flux can be done in the gap of air, the field element can include any stable magnets otherwise, electromagnets which are shaped with a conducting coil like another armature which is known as a doubly-fed electric machine. the armature always works like a conductor, sloping normal toward both the field as well as toward the motion direction, torque otherwise force. The armature diagram is shown below.


The main role of an armature is multi purposed. The primary role is to transmit current across the field, therefore generating shaft torque within an active machine otherwise strength in a linear machine. The second role of an armature is to produce an EMF (electromotive force). In this, an EMF can occur with the armature’s relative motion as well as the field. As the machine is employed as a motor, then the EMF will oppose the current of an armature and converts the electric power into mechanical which is in the form of torque, and finally transmits through the shaft.

Whenever the machine is utilized like a generator, then the armature electromotive force drives the current of an armature, as well as the movement of the shaft will be changed to electrical power. In the generator, the power which is produced will be drawn from the stator. A growler is mainly used to ensure the armature intended for opens, grounds, as well as shorts.

Armature Components

An armature can be designed with the number of components namely the core,  the winding, the commutator, & the shaft.

Armature Parts
Armature Parts

The Core

The armature core can be designed with many thin metal plates which are named as laminations. The thickness of laminations are approximate 0.5mm and it depends on the frequency by which the armature will be designed to work. The metal plates are stamped-out on a push.


They are in the circular form by a hole stamped-out of the core, while the shaft is pressed, as well as the slots which are stamped in the region of the edge wherever the coils will finally sit. Metal plates are associated together to generate the core. The core can be built with stacked metal plates instead of using a steel piece to produce the sum of lost energy while heat in the core.

The loss of energies is known as iron losses which are occurred by eddy currents. These are minute turning magnetic fields forms in the metal because of the revolving magnetic fields which can be found whenever the unit is running. If the metal plates use the eddy currents then they can form in one plane as well as significantly reduces the losses.

The Winding

Before the process of winding starts then the core slots will be protected from the copper wire within the slots approaching into contact by the laminated core. Coils are placed into the armature slots as well as attached to the commutator in revolving. This can be done in many ways based on the armature design.

Armatures are classified into two types namely lap wound armature as well as wave wound armature. In a lap wound,  the final end of one coil is attached toward the segment of a commutator as well as the primary end of the nearby coil. In a wave wound, the coils two ends will be associated with the segments of the commutator which are divided by some distance among the poles.

This permits the sequence adding of the voltages within the windings among brushes. this kind of winding needs only one couple of brushes. In the first armature, the number of lanes equals the number of poles as well as brushes. In some of the armature designs, they will have two or more different coils in a similar slot, attached to nearby commutator segments. This can be done if the required voltage across the coil will be considered to be high.

By distributing the voltage over three separate segments as well as coils will be in the same slot, the strength of the field in the slot will be high, however, it will decrease arcing over the commutator, as well as make the device more competent. In several armatures the slots are also twisted, this can be attained with every lamination being somewhat out of line up. This can be done to decrease cogging, as well as provide a level revolution from one to another pole.

The Commutator

The commutator is pushed on top of the shaft as well as it is held on by a coarse knurl similar to the core. the designing of commutator can be done using copper bars, and an insulating material will separate the bars. Normally, this material is a thermoset plastic however in older armatures sheet mica has been used.

The commutator has to be accurately associated by the core slots whenever pushed on top of the shaft because the wires from every coil will appear from the slots as well as attach with the commutator bars. To work the magnetic circuit efficiently, it is essential that the armature coil has a precise angular displacement from the commutator bar toward which it is attached.

The Shaft

The shaft of an armature is one kind of hard rod mounted among two bearings that describe the axis of components placed onto it. It should be broad sufficient to send out the torque necessary with the engine & rigid adequate to control some of the forces which are out of balance. For harmonic distortion, the length, speed, and bearing points are selected  An armature can be designed with a number of major components namely the core, the winding, the shaft, and the commutator.

Armature Function or Armature Working

The armature rotation can be caused by the communication of two magnetic fields. One magnetic field can be generated by the field winding, whereas the second can be produced with the armature while voltage is applied toward the brushes to get in touch with the commutator. Whenever the current supplies through the winding of an armature, then it creates a magnetic field. This is out of line by the field created with the field coil.

This will cause the power of attraction toward a single pole as well as revulsion from the other. When the commutator is connected to the shaft then it will also move with a similar degree as well as activates the pole. The armature will continue to chase the pole to spin.

If the voltage is not given to the brushes then the field will get excited as well as the armature will be driven mechanically The voltage which is applied is AC because it approaches, and flows away from the pole. However, the commutator being associated with the shaft and frequently activates the polarity because it revolves, like that the real output can observe across the brushes in DC.

Armature Winding and Armature Reaction

The armature winding is the winding where the voltage can be induced. Similarly, the field winding is the winding where the main field flux can be generated whenever the current flows through the winding. The armature winding has some of the basic terms namely turn, coil and winding.

Armature reaction is the result of the armature flux on top of main field flux. Generally, the DC motor includes two windings such as Armature winding as well as field winding. Whenever we stimulate the field winding, then it generates a flux which connects by the armature, and this will cause an emf & therefore a flow of current in the armature.

Applications of Armature

The applications of an armature include the following.

  • The armature is used in an electric machine for generating power.
  • The armature can be used as rotor otherwise stator.
  • This is used to monitor the current for the applications of DC motor.

Thus, this is all about an overview of an armature which includes what is an armature, components, working, and applications. From the above information finally, we can conclude that an armature is an essential component used in an electric machine for generating power. It can be on either the rotating part otherwise stationary part of the machine. Here is a question for you, how armature works?