Applications of Eddy Current

What are the applications of eddy current? Here in this article we are discussing about the various applications of eddy current with its disadvantage and method of minimizing the eddy current. Eddy current are useful in many ways though they have some disadvantages too. Some of the important applications of eddy currents are: Electromagnetic Damping This is used in designing dead beat galvanometers. When a steady current is passed through the coil of galvanometer, it is deflected. Normally, the coil oscillates about its equilibrium position for some time before coming…

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Construction of DC Machines Question and Answer

4 pole DC machine

Construction of DC Machine Short Answer type Question and Answer: 25 Short answer question and highlight point on construction of DC machines Q.1 On what principle does the generator operate? Ans. The generator operates on the principle of production of dynamically induced emf. Q.2 Why it is necessary to use a large number of coils and commutator segment with the coils evenly distributed around the surface of the armature of a dc machine? Ans: It is done so as to have practically constant unidirectional voltage at the brushes. Q.3 Why…

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Wave Winding | Series Winding of DC Machine

developed view of 4-pole, double layer, simplex wave winding with 30 coil slides

Wave winding is also sometimes known as series winding. In lap winding a coil side under one pole is connected directly to a coil side which occupies a nearly corresponding position under the next pole by means of back connections, and this second coil is then connections, and this second coil is then connected back through the commutator segment, to a coil side under the original pole, but removed two or more coil sides from the initial one. But in a wave winding the coil side is not connected back…

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Equalizer Connections in Lap Winding

simplex lap winding with equalizer connections

In lap winding all the conductors in any parallel path lie under one pair of poles. If flux from all the poles is exactly the same, the induced emf in each path hence current carried by each path will be equal. Equalizer Connections in Lap Winding But inspite of best effort this condition is not practicable either due to variation in gap length or due to different magnetic properties of steel. The currents flowing in various paths may also differ due to difference in their resistances. Hence there is always…

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Simplex Lap Winding | Characteristic

Characteristics of Simplex Lap Winding From the winding diagram shown in previous post the following conclusions regarding simplex lap winding are arrived at: The winding starting from any coil side returns back to that very coil side after connecting all the coil sides once and only once hence it is singly re-entrant closed winding. Back pitch and front pitch of all the coils remain the same and odd number.  The total number of brushes is equal to the number of poles, and the brushes are connected to the coil sides,…

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Winding Drawing | How to Draw?

equivalent ring or spiral winding

In order to draw the winding diagram, first of all draw the coil sides and number them. Now to make connections start from any coil side, say with first coil side. In order to get the coil side to which the 1st coil side is to be connected at the back, add back pitch to it. So first coil side will be connected to the 1 + 7=8th coil side at the back by means of end connections. In order to get the coil side to which 8th coil side…

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Types of Armature Winding | Drum | Lap Winding

Armature winding are always of the non-salient pole type and usually are symmetrically distributed in slots around the complete circumference of the armature. The armature winding, according to the degree of closure produced by the winding to the degree of closure produced by the winding, are of two types of armature winding namely: (a) Open coil winding (b) Closed coil winding. Open coil winding is that winding which does not close on itself i.e. a close circuit will not be formed until some external connection is made to a source…

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What is Armature Winding? | Terminology

armature winding

Armature Winding Armature winding is an arrangement of conductors to develop descried emfs by relative motion in a heteropolar* magnetic field. In winding, conductor or group of conductors are distributed in different ways in slots all over the periphery of the armature. The conductors may be connected in series and parallel combinations depending upon the current and voltage rating of the machine. Terminology It is necessary to understand some of the important terms before discussing winding. The most commonly used term in describing a winding are given below. Conductor. Each individual…

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What are the Essential Part of DC Machine | Explanation

4 pole DC machine

Here in this article we explain about essential parts of DC machine with construction details and image. What are the essential parts of DC Machine? Essential parts are Field magnet, armature, commutator, brush and brush gear, bearing and shaft. DC machine (whether a generator or motor) with four poles is shown in Fig. 1. In construction, dc machine consists of four parts mainly Field magnets Armature Commutator Brush and brush gear. Figure 1: 4-Pole DC Machine Disassembled dc machine is shown in Fig. 2. Figure 2: DC Machine (Disassembled) 1.…

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Simple Loop Generator | DC Machine

armature coil in neutral plane

In this article we are discussing about simple loop generator of DC machine, we had also show how EMF is generated in a simple DC generator. A signal turn rectangular copper conductor loop ABCD routing in clockwise direction about its own axis XX’ in the uniform magnetic field is shown in figure below. As the coil is rotated in the magnetic field by some mechanical means (not shown in the Fig.) the flux linking with the loop changes continually, therefore, an emf is induced in it. The magnitude of emf…

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