ARMATURE REACTION IN D.C.MACHINES PDF

Armature Reaction is the effect of magnetic flux set up by armature current The brushes of the DC machines are always placed in this axis, and hence this axis. armature reaction mmf gets added at this tip leading to considerable amount In some small d.c. machines the brushes are shifted from the position of the mag-. Commutation problem is not the only problem in DC machines. At heavy loads, the cross magnetizing armature reaction may cause very high.

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The first method is to shift the position of the brushes so that they are in the neutral plane when the generator is producing its normal load current. Due to these limitations, this method is generally not preferred. Copper armature wiring enhances electrical efficiencies due to its higher electrical conductivity. In a DC machinetwo kinds of magnetic fluxes are present; ‘armature flux’ and ‘main field flux’.

Now, when a DC machine is running, both the fluxes flux due to the armature conductors and flux due to the field winding will be present at a time. So, when applying a produced by conductor is against the main field at lower side torque, loading on electrical side should reflect as load of the conductor while it adding with the main field at upper torque, such that the prime mover should supply extra torque side of the conductor.

From Wikipedia, the free encyclopedia. Thus in this case compensation windings are installed in slots of the poles faces of main field poles. Due to motion of coil, current induced in the conductors of the coil which flow through the brushes and to the external circuit. Alternator Electric generator Inchworm motor.

The armature must carry currentso it is always a conductor or a conductive coil, oriented normal i both the field and to the direction of motion, torque rotating machineor force linear machine. C machine shaft energy coming from mechanical conductor is placed in magnetic field and let the current domain goes into the magnetic domain, and then finally flowing through it as shown in figure Because the load current is varying quantity which means the flux due to armature current which indicating orthogonal to the north-south flux the amplitude keeps varying.

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CONCEPT OF ARMATURE REACTION IN DC MACHINES | eSAT Journals –

Views Read Edit View history. Now a resultant flux is known and therefore orthogonal to the plane is this and these would be neutral zone which is shown in Fig. The armature can be on either the rotor rotating part or the stator stationary part of the electric machine. Leave a comment Click here to cancel reply.

The direction of current induces in the conductor is given by the Fleming right-hand rule. When the field flux enters into the armature, they may get distorted. Your email address will not be published. Brush shift has serious limitations, so the brushes have to be shifted to a new position every time the load changes or the direction of rotation changes or the mode of operation changes. The north-south poles and conductors are in circular armature.

Help Center Find new research papers in: The direction of current remains same in all the conductors which lying under one pole.

On the left hand side of neutral zone, the flux is creating rings around conductors because there is current flowing within this loops and the direction x.c.machines in clockwise which is given by the right hand rule. Aluminum armature wiring is lighter and less expensive than copper.

Armature (electrical) – Wikipedia

Doubly-fed Linear Servomotor Stepper Traction. There by still maintaining the same neutral zone position and thereby do not shift position of the brush and the brushes can still stand same position and the voltages induced in the coil at the neutral zone to still the zero and therefore no short d.x.machines current and therefore also no sparking or arcing when the commutator segment are passing over the brushes at that point that is the neutral zone [1] [3] [5].

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In flows through the conductor is shown in Fig. D.c.machinds a “lap” winding, there are as many current paths between the brush or line connections as there are poles in the field winding.

Armature Reaction in a DC Generator

The armature reaction changes the distribution of the magnetic field, which affects the operation of the machine. Armature reaction effects the normal operation of DC Generator in many ways.

Although distinctly separate these two sets of terminology are frequently used interchangeably or in combinations that include one mechanical term and one electrical term.

Enter the email address you signed up with and we’ll email you a reset d.c.machinrs. Similarly, the density of flux decreases in the lower pole tip of the north pole and the upper pole tip of the south pole. As shown in Fig. Leave a Reply Cancel reply Your email reacction will not be published.

The magnetic axis means the centre line between the north and south pole. So this amplitude keeps varying then the resultant could be in any direction depending upon the amount of load current as shown in Fig.

Since an armature is wound with coils of wire, a magnetic field is set up in the armature whenever a current flows in the coils.

This would ultimately result into a net reduction in flux per pole. Circuit Globe All about Electrical and Electronics. In no load condition, the magnetic neutral axis coincides with the geometrical neutral axis. Now, inside the centre of armature of machine because of all the fluxes are pointing up, it means there is an effective flux which is pointing in upward direction.