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Commutating field windings are connected in series with the armature windings so that the current flowing in the coils is always equal to the armature current. The number of turns in the commutating field windings are also equal to the number of armature turns. This means that the field strength of the commutating windings and the field strength of the armature are always equal. A DC motor is constructed so that these two fields of equal strength oppose one another, they therefore cancel one another out. The main field is now unaffected by armature reaction.
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What is armature reaction in dc machines?
Armature reaction is the phenomenon in DC machines where the magnetic field produced by the current flowing in the armature windings interacts with the main magnetic field produced by the field windings. This interaction can distort the main magnetic field, causing changes in the machine's performance such as voltage regulation and torque production. Measures such as interpoles or compensating windings are used to counteract the effects of armature reaction in DC machines.
Which effect of the electric current is used in electric bell?
The electromagnet effect is used in an electric bell. When the current flows through the coil, it creates a magnetic field that attracts the iron armature, causing the bell to ring.
Do enzymes affect the thermodynamics of a reaction true or false?
False. Enzymes do not affect the thermodynamics of a reaction. They only lower the activation energy required for the reaction to proceed, thereby increasing the rate of the reaction without changing the equilibrium constant or overall energetics of the reaction.
What is the effect of variable area to the magnetic flux within the solenoid at constant number of windings and current?
Increasing the variable area of the solenoid will result in a change in the magnetic flux within the solenoid while keeping the number of windings and current constant. This is because the magnetic flux is directly proportional to the cross-sectional area of the solenoid. Therefore, as the area increases, the magnetic flux will also increase, and vice versa.
How do different lengths of string effect a pendulums swing?
As the length of the string (or armature) of the pendulum increases the rotational speed of the pendulum decreases proportionately if the velocity of the weight remains the same. Example: a pendulum operating a clock is rotating too fast. The clock is running fast as a result. by sliding the pendulum weight out away from the fulcrum (lengthening the armature in effect) the pendulum slows and corrects the time keeping accuracy of the clock. * note: Metronomes operate using this principle as well.
What are compensating winding?
compensating windings are used to overcome armature reaction
What is armature reaction in dc machines?
Armature reaction is the phenomenon in DC machines where the magnetic field produced by the current flowing in the armature windings interacts with the main magnetic field produced by the field windings. This interaction can distort the main magnetic field, causing changes in the machine's performance such as voltage regulation and torque production. Measures such as interpoles or compensating windings are used to counteract the effects of armature reaction in DC machines.
What is the use of interpoles in dc machine?
Interpoles are similar to the main field poles and located on the yoke between the main field poles. They have windings in series with the armature winding. Interpoles have the function of reducing the armature reaction effect in the commutating zone. They eliminate the need to shift the brush assembly.
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
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.
How you can reduce the effect of armature reaction?
by using capacitor
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.
What is the purpose of Inter-pole fitted in a DC generator?
to chancel the effect of the armature reaction.
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 a Line Commutating Choke?
Line commutating chokes are used to smooth voltage peaks or bridge commutating dips. In effect, this reduces the effects of harmonics on the inverter and power supply. A line commutating choke is necessary to reduce current peaks if line impedance is <1%
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.
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.
