Home » Free download » armature

armature

Download-Button

Armature: The Winding of an Electric Machine


Armature: The Winding of an Electric Machine

An armature is a vital component of an electric machine, such as a motor or a generator, that carries alternating current (AC). The armature interacts with the magnetic field generated by the permanent magnets or the electromagnets in the machine, and produces torque or electromotive force (EMF) depending on whether the machine is used as a motor or a generator.

In this article, we will explore the definition, function, and types of armatures, and how they work in different kinds of electric machines.

Definition of Armature

According to Merriam-Webster, the word armature has several meanings, but in electrical engineering, it refers to “a usually rotating part of an electric machine (such as a generator or motor) which consists essentially of coils of wire around a metal core and in which electric current is induced or in which the input current interacts with a magnetic field to produce torque”.

The armature can be either on the rotor (the rotating part) or the stator (the stationary part) of the machine, depending on the type and design of the machine. The armature windings are usually made of copper or aluminum, and are connected to a commutator or a slip ring that allows the current to flow in and out of the armature.

Function of Armature


Definition of Armature

The main function of the armature is to carry current across the magnetic field, thus creating mechanical power in the form of torque (rotating machine) or force (linear machine). The armature also generates an EMF due to the relative motion between the armature and the field. This EMF can either oppose or drive the armature current, depending on whether the machine is used as a motor or a generator.

When the machine is used as a motor, the armature receives current from an external source, such as a battery or a power supply, and converts it into mechanical power that rotates the shaft. The EMF generated by the armature opposes the input current, and is known as back EMF or counter EMF. The back EMF limits the amount of current that flows through the armature, and thus regulates the speed of the motor.

When the machine is used as a generator, the armature rotates due to an external force, such as wind or water, and converts it into electrical power that can be delivered to a load. The EMF generated by the armature drives the output current, and is known as induced EMF or generated EMF. The induced EMF depends on the speed of rotation and the strength of the magnetic field.

Types of Armature


Function of Armature

There are different types of armatures depending on the type and design of electric machines. Some common types are:

  • Lap winding: A type of armature winding where each coil is connected to two commutator segments that are spaced apart by the number of poles. This type of winding is suitable for high-current and low-voltage machines.
  • Wave winding: A type of armature winding where each coil is connected to two commutator segments that are spaced apart by approximately half the number of commutator segments. This type of winding is suitable for low-current and high-voltage machines.
  • Drum winding: A type of armature winding where coils are arranged on a cylindrical surface and connected to commutator segments. This type of winding can be either lap or wave depending on how coils are connected.
  • Disk winding: A type of armature winding where coils are arranged on a flat disk and connected to slip rings. This type of winding is used for AC machines.
  • Pole winding: A type of armature winding where coils are wound around individual poles instead of being distributed over
    the entire surface. This type of winding is used for DC machines with salient poles.

Examples of Armature


Types of Armature

Some examples of electric machines that use armatures are:

Leave a Reply

Your email address will not be published. Required fields are marked *

*
*