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Types of Armature Winding: AC and DC Armature Winding and Types of Winding and Comparasion

Introdcution to Armature Winding

Basically the first question is what is armature winding? Armature winding is an one type of arrangement of conductors to produce emf by relative motion in hetropolar magnetic field.

The armature is provided with slots on its circumference in which the conductors are housed. These conductors are connected by two methods according to our requirement:

  1. Connected in series for increasing voltage ratings.
  2. connected in parallel for increasing current ratings.

Comparision between closed and open winding

Comparison between open windings and closed windings

Closed Winding Open Winding

Closed path around the armature periphery

open at one or more points forming several sections

winding are double layer type

can be single or double layer type

used in D.C. machines

used in A.C. Machine

not flexible design

flexible design

types of armature winding- dc armature winding- lap and wave

types of armature winding- dc armature winding- lap and wave

Types of D.C. Armature Winding

D.C. winding are classified by two ways according to how conductors are connected:

  1. lap Winding ("series winding")
  2. wave winding ("multiple winding" or "parallel winding")

In lap winding number of parallel paths are high. and here Number of parallel path (A) = Number of poles (P). Because of this reason this winding is also called as "multiple winding" or "parallel winding".

In wave winding number of parallel paths is two (A=2). that's why it is also called as "series winding".

Lap winding is suitable when requirement is : large d.c. currents and low voltage.

wave winding is suitable when requirement is: low d.c. current and high voltage.

  • Advantage of using wave winding:
  1. For given number of poles and armature conductors, it gives EMF more than lap winding.
  2. equalizer connections are not necessary (whereas in lap winding they are used.)

In case of wave winding, Dummy coil is used to provide mechanical balance to the armature winding.

Introduction to AC armature winding

In ac machines, the stator has ac armature winding in which the alternating emf is induced. The winding for armature of a dc machines is closed and the closed windings are always double layer type. The armature used for armature of ac machines is open.

open layer can be either single layer or double layer. The stator winding consists of single turn or multi turn coils, arranged in slots and connected properly so as to obtain the required phase grouping. The AC winding must be properly arranged, so that the emf induced in all the phases are of equal magnitude and frequency. The emfs of all the m phases of ac machine must have identical wave-shape and displaced in time phase by (2 * pie/m).

Why it is called open coil winding?

In ac machines the wave shape of the generated emf depends upon the flux distribution in the air-gap of a machine. In ac winding the ends of the first coil and last coil or the beginning of the first coil and the ending coil of the last coil is kept open, so this is know as open coil winding.

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armature winding books I recommend

Types of AC armature winding

There are basic two types of AC armature winding:

  1. Single layer winding
  2. Double layer winding

This are further classified as below:

1. Single layer winding:

  • Concentric windings:

1. Hermitropic winding or half coil winding

2. Whole coil winding

  • Mush winding

2. Double layer winding:

  • Lap winding:

1. integral slot winding

2. Fractional slot winding

  • Wave Winding:

1. integral slot winding

2. Fractional slot winding

This was all about Armature AC and DC winding. I have also written classification of each winding. and also compared closed and open winding. I hope this article is useful to readers who are electrical engineer particularly.


musha on December 22, 2018:

we wanted to see a practical diagram of a dc fan, ac grinder and a juicer armature. theoretical learning is not our subject.

Thomas Alula on June 10, 2017:

Nice I like it

D on September 17, 2016:

I hope their is more pictures for us to understand more the types of coils (Open and Closed, wave, etc)

binal modi on August 18, 2015:

give me detail design of fractional slot winding

idris sk on June 08, 2015:

In future i make in ohms law modifide defrently and transfamer .changes in electritronic and electrical.i hope that

Idris sk.

Braja Sahoo on April 30, 2015:

I like it too

Rohini kokane on April 13, 2015:

nice....i like it

dhiraj chaudhary on August 15, 2014:

Single layer winding is used for closed slots whole two layer winding is used in open slote. Half top of the slots and half bottom of the slotd

Man singh on July 28, 2014:

best for interview answere

Attharuddin on April 01, 2014:

its very useful and good

balu on March 12, 2014:


Forthefuture (author) from India on June 04, 2013:

Thank you rafiya islam for your comment.

Rafiya Islam on May 30, 2013:

dat was good.

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