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

Author:
Forthefuture
Updated date:
May 11, 2013

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:

Connected in series for increasing voltage ratings.
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
electromechanicalenergyconversion

Types of D.C. Armature Winding

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

lap Winding ("series winding")
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:

For given number of poles and armature conductors, it gives EMF more than lap winding.
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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Types of AC armature winding

There are basic two types of AC armature winding:

Single layer winding
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.