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Remedies for Armature reaction?
To reduce the effects of armature reaction is to place small auxiliary poles called"interpoles" between the main field poles. The interpoles have a few turns of large wire and are connected in series with the armature. Interpoles are wound and placed so that each interpole has the same magnetic polarity as the main pole ahead of it, in the direction of rotation. The field generated by the interpoles produces the same effect as the compensating winding. This field, in effect, cancels the armature reaction for all values of load current by causing a shift in the neutral plane opposite to the shift caused by armature reaction. The amount of shift caused by the interpoles will equal the shift caused by armature reaction since both shifts are a result of armature current.
What do interpoles do in DC motors?
Interposes are used in DC Machines to reduce the effect of armature reaction and self induction, mainly in winding at commutators,of DC motors.Interpoles are connected in series with armature winding so that as the armature current changes the flux due to interpoles chances accordingly.Interpoles are temporary magnets,generally placed in between two consecutive poles.
How is an alternating current produced?
EMF is induced in a coil when it is rotated in magnetic field. The magnetic field is obtained in the space between N Pole and S Pole of a magnet. coil is kept on shaft and it is rotated. To take out the current from the coil, two slip rings made of brass are kept on the shaft. The slip rings are insulated from each other and from the shaft. Carbon brushes are placed on the slip ring. EMF is available across these brushes. Load is connected across the brushes. This is called single phase type alternator or AC Generator. In practice three phase type alternator is used. In alternator, used in power stations, armature is kept stationary and field is rotated.
Why are brushes staggered on commutator?
To avoid sparking they need to be placed at zero point
What special instrument is placed inside the heart and used as impulse generator to make it function normally?
The special instrument that is placed in the heart and used as a impulse generator is called pacemaker. The pacemaker helps the heart to make it fuction normally....
Why is brushes placed at MNA in a dc generator?
to avoid sparking ,since their is no e.m.f induced in magnetic neutral axis.
Define the brush on a dc motor?
The brush is actually a piece of carbon placed on the rotating commutator of the motor. it will be in pairs. Since the armature shaft rotates but gets the continuity through these brushes.
Answering Which one is a separately excited generator - ac generator or dc generator?
Excitation is the phenomenon by which you control the excitation of field winding of a generator. In DC generator field winding is placed on stator and this field winding can be self excited or seperately excited depending upon the type on generator used. AC generators can also be self excited or seperately excited type but field winding is placed on rotor nad armature winding on stator.
Remedies for Armature reaction?
To reduce the effects of armature reaction is to place small auxiliary poles called"interpoles" between the main field poles. The interpoles have a few turns of large wire and are connected in series with the armature. Interpoles are wound and placed so that each interpole has the same magnetic polarity as the main pole ahead of it, in the direction of rotation. The field generated by the interpoles produces the same effect as the compensating winding. This field, in effect, cancels the armature reaction for all values of load current by causing a shift in the neutral plane opposite to the shift caused by armature reaction. The amount of shift caused by the interpoles will equal the shift caused by armature reaction since both shifts are a result of armature current.
What is an armature made of?
The armature is the part of an electric generator or motor that contains the main current-carrying winding. It usually consists of a coil of copper wire that is wound around an iron or steel core. The coil and core are placed in a magnetic field, which is produced by one or more permanent magnets or electromagnets.
What do interpoles do in DC motors?
Interposes are used in DC Machines to reduce the effect of armature reaction and self induction, mainly in winding at commutators,of DC motors.Interpoles are connected in series with armature winding so that as the armature current changes the flux due to interpoles chances accordingly.Interpoles are temporary magnets,generally placed in between two consecutive poles.
What are the parts of an alternator?
In an alternator, there are two main parts, one is stationary part and other is rotating part. Field winding may be placed on fixed part(stator) as in case of DC generator and on rotating part(rotor) as in case of AC genarators. Armature winding may be placed on rotating part(rotor) in case of DC generator and on stationary part (stator) in case of AC generator. In AC generators, for all practical purposes you have rotating filed system.
How is an alternating current produced?
EMF is induced in a coil when it is rotated in magnetic field. The magnetic field is obtained in the space between N Pole and S Pole of a magnet. coil is kept on shaft and it is rotated. To take out the current from the coil, two slip rings made of brass are kept on the shaft. The slip rings are insulated from each other and from the shaft. Carbon brushes are placed on the slip ring. EMF is available across these brushes. Load is connected across the brushes. This is called single phase type alternator or AC Generator. In practice three phase type alternator is used. In alternator, used in power stations, armature is kept stationary and field is rotated.
Why are brushes staggered on commutator?
To avoid sparking they need to be placed at zero point
Why are the brushes of a dc machine always placed at the neutral points?
The function of brush is to collect current from rotating commutator and supplies the current to external stationary load. The brushes of a DC machine are placed at neutral points because the current in the rotating part drops to zero at the neutral point. If brushes are placed in location other than the neutral points, then the current may be switched off and it causes magnetic field and it may also create voltage spikes and arc at brushes.
What kind of reaction occurs when potassium is placed in water?
it is a decomposistion reaction.
Where does one place the emergency generator?
An emergency generator is a type of machine that helps generate emergency electricity. Most emergency generators are gas powered. Therefore, they should be placed in a well-ventilated area. Usually, they are placed on a back porch or in a garage. They should not be placed inside a home.
