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By Using Interpoles (Auxillary Poles).......
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What are compensating winding?
compensating windings are used to overcome armature reaction
What is armature reactions in a synchronous machine?
Armature reaction is the effect of armature flux on the flux generated by the fied windings.Cross magnetisation and Demagnetising are its consequences.
Remedies for Armature reaction?
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 field is at right angles to the generator field, and is called cross magnetization of the armature. The effect of the armature field is to distort the generator field and shift the neutral plane. The neutral plane is the position where the armature windings are moving parallel to the magnetic flux lines. This effect is known as armature reaction and is proportional to the current flowing in the armature coils. The brushes of a generator must be set in the neutral plane; that is, they must contact segments of the commutator that are connected to armature coils having no induced emf. If the brushes were contacting commutator segments outside the neutral plane, they would short-circuit "live" coils and cause arcing and loss of power. Armature reaction causes the neutral plane to shift in the direction of rotation, and if the brushes are in the neutral plane at no load, that is, when no armature current is flowing, they will not be in the neutral plane when armature current is flowing. For this reason it is desirable to incorporate a corrective system into the generator design. These are two principal methods by which the effect of armature reaction is overcome. 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. in the other method, special field poles, called interpoles, are installed in the generator to counteract the effect of armature reaction. The brush-setting method is satisfactory in installations in which the generator operates under a fairly constant load. If the load varies to a marked degree, the neutral plane will shift proportionately, and the brushes will not be in the correct position at all times. The brush-setting method is the most common means of correcting for armature reaction in small generators (those producing approximately 1000 W or less). Larger generators require the use of interpoles.
Why are the compensating winding used in dc motor?
compensating winding is used for equal load sharing of two generators running in parallel. while interpole winding is used to minimise the effect of armature reaction by supporting the main field.
What is the demagnetizing component of armature reaction?
it is the flux which is flowing opposite to the main field flux and demaganetize it... in order to eliminate this demagnetiszing component we have to connect the compensating winding in series with the armature winding which develop the flux in it oppose to the demagnetizing component
Why pole face are chamfered in dc machine?
in order to reduce armature reaction.
How you can reduce the effect of armature reaction?
by using capacitor
What are the effect of armature reaction in DC machine and how the armature reaction is minimise?
Armature reaction is the interaction between the magnetic flux produced by armature current and that of the main magnetic field in an electric motor or generator.
What is the difference between armature reaction and armature reactance?
armature reactant means loss in armature associated with inductive properties of the coil, while armature reaction include losses due to magnetizing component of current flowing through armature.
Why the induction motor does not have armature reaction?
Because the armature (or rotor) has no external connection. The currents that produce torque from the rotor are induced by the magnetic field in the machine, so there is no commutator, no brushes and no armature reaction.
What is mean by armature reaction?
armature reaction means when load is added to the armature then current is passed through armature conductors then in armature creates flux. It is demagnetize and cross magnetize the main field flux. in other ward it is effect of armature field on main field.
What are compensating winding?
compensating windings are used to overcome armature reaction
What is armature reaction in dc machines?
The armature reaction is the interaction between armature flux and field flux when current is introduced to a dc motor. It results in a cross-magnetizing effect and a demagnetizing effect.
What is armature reactions in a synchronous machine?
Armature reaction is the effect of armature flux on the flux generated by the fied windings.Cross magnetisation and Demagnetising are its consequences.
Armature reaction in a DC generator?
ARMATURE REACTION in DC MachineAll current-carrying conductors produce magnetic fields. The magnetic field produced by current in the armature of a dc generator affects the flux pattern and distorts the main field. This distortion causes a shift in the neutral plane, which affects commutation. This change in the neutral plane and the reaction of the magnetic field is called armature reaction.
The armature of DCgenerator is laminated to?
Reduce the eddy current less
What is armature reaction in dc motor?
Armature reaction is effect of armature flux on main field flux. Basically there are two windings in a dc motor - Armature winding (on stator) and field winding (on rotor). When we excite the field winding, it produces a flux which links with the armature. This causes an emf and hence a current in the armature. This current in armature produces another flux which lags the main flux. This is referred to as armature reaction. It has two effects on the machine: 1. Demagnetising effect: It reduces the strength of the main flux. 2. Crossmagnetising effect: Its effect is that it bends/distortes the the main flux line along the conductor
