What is armature reaction?

What is armature reaction?
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1 Answer

Answer :

Distortion of the main field due to the effects of armature current.
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Related questions

Armature reaction in a dc motor causes a shift of the neutral plane in which direction?

Description : Armature reaction in a dc motor causes a shift of the neutral plane in which direction?

Last Answer : Opposite the rotation.

How is the disadvantage of the Gramme-ring armature overcome in the drum-wound armature?

Description : How is the disadvantage of the Gramme-ring armature overcome in the drum-wound armature?

Last Answer : By winding the armature in a way that places the entire coil where it is exposed to maximum flux.

Why is the Gramme-ring armature not more widely used

Description : Why is the Gramme-ring armature not more widely used

Last Answer : Only outside of coils cut flux (inefficient).

Why are drum-type armatures preferred over the Gramme ring armature in modern dc generators?

Description : Why are drum-type armatures preferred over the Gramme ring armature in modern dc generators?

Last Answer : Drum-type armatures are more efficient, because flux lines are cut by both sides of each coil.

In single-phase alternators, in order for the voltages induced in all the armature windings to add together for a single output, how must the windings be connected?

Description : In single-phase alternators, in order for the voltages induced in all the armature windings to add together for a single output, how must the windings be connected?

Last Answer : In series.

A loss of field excitation to an AC generator while operating in parallel will cause it to ____________. A. absorb more and more load due to decreased armature reaction B. lose its load due to the inherent speed droop built into the governor C. smoke and overload due to field flashover as residual field flux changes polarity D. lose its load, begin to motorize, trip out on reverse power relay, and possibly overspeed

Description : A loss of field excitation to an AC generator while operating in parallel will cause it to ____________. A. absorb more and more load due to decreased armature reaction B. lose its load due to ... polarity D. lose its load, begin to motorize, trip out on reverse power relay, and possibly overspeed

Last Answer : Answer: D

The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Description : The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Last Answer : Answer: C

The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Description : The armature cores of the D.C. motors are constructed with laminations to ___________. A. eliminate hysteresis B. minimize brush sparking C. reduce eddy current losses D. compensate for armature reaction

Last Answer : Answer: C

As an armature revolves within a magnetic field, friction is developed between the rotated magnetized particles as they pass through each magnetization cycle. This results in ____________. A. copper loss B. eddy-current loss C. hysteresis loss D. armature reaction

Description : As an armature revolves within a magnetic field, friction is developed between the rotated magnetized particles as they pass through each magnetization cycle. This results in ____________. A. copper loss B. eddy-current loss C. hysteresis loss D. armature reaction

Last Answer : Answer: C

The purpose of DC generator brushes is to _____________. A. neutralize armature reaction B. conduct electric current to an outside circuit C. convert DC current to AC current D. provide excitation to a DC generator

Description : The purpose of DC generator brushes is to _____________. A. neutralize armature reaction B. conduct electric current to an outside circuit C. convert DC current to AC current D. provide excitation to a DC generator

Last Answer : Answer: B

In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors

Description : In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors

Last Answer : Answer: C

Regarding an AC generator connected to the main electrical bus; as the electric load and power factor vary, a corresponding change is reflected in the generator armature reaction. These changes in armature reaction are compensated for by the __________ A. governor speed droop setting B. voltage regulator C. balance coil D. phase-balance relay

Description : Regarding an AC generator connected to the main electrical bus; as the electric load and power factor vary, a corresponding change is reflected in the generator armature reaction. These changes in ... . governor speed droop setting B. voltage regulator C. balance coil D. phase-balance relay

Last Answer : Answer: B

What is meant by armature reaction?

Description : What is meant by armature reaction?

Last Answer : Answer: The action of armature m.m.f. on the main m.m.f. is known as armature reaction.

What Is Meant By Armature Reaction?

Description : What Is Meant By Armature Reaction?

Last Answer : What Is Meant By Armature Reaction? The effect of armature flu to main flux is called armature reaction. The armature flux may support main flux or opposes main flux.

Explain armature reaction of an alternator and its effect on main flux at various power factor.

Description : Explain armature reaction of an alternator and its effect on main flux at various power factor.

Last Answer : 1. zero lagging pf: armature flux lags main flux by 180 . Hence effect is demagnetizing i.e the main flux is reduced 2. lagging pf: it has 2 components demagnetizing and cross magnetizing ... 5. zero leading pf: Armature flux is in phase with main flux. Effect is completely magnetizing.

What is meant by armature reaction in Alternators?

Description : What is meant by armature reaction in Alternators?

Last Answer : The effect of armature flux on main flux

What is meant by Armature reaction?

Description : What is meant by Armature reaction? 

Last Answer : The effect of armature flux on the main field flux is called Armature reaction, where armature flux weakens the main field flux. In Alternator power factor contributes more importance in Armature reaction. ... has to be reduced. Otherwise end parts or overhang portion of the generator will heat.  

What are the remedies for armature reaction?

Description : What are the remedies for armature reaction? 

Last Answer : a. Brushes have to shift to new M.N.A position in the direction of rotation of armature. b. To over come the weakening of the field extra turns have to be added in armature. c. ... in series with the armature winding such that the current in that winding is opposite to the armature winding.

What is armature reaction?

Description : What is armature reaction?

Last Answer : Armature reaction is the effect of armature flux on the main field flux. The effects of armature reaction are follows. a. Armature reaction destroys (cross magnetizes) and weakens the main ... self-excited generators de-magnetising of pole cores (wiping of residual magnetism) may takes place. 

Reduction in the capacitance of a capacitor-start motor, results in reduced (A) Noise. (B) Speed. (C) Starting torque. (D) Armature reaction.

Description : Reduction in the capacitance of a capacitor-start motor, results in reduced (A) Noise. (B) Speed. (C) Starting torque. (D) Armature reaction.

Last Answer : Ans: C Reduction in the capacitance reduces starting voltage, which results in reduced starting torque.

In DC generators, armature reaction is produced actually by (A) Its field current. (B) Armature conductors. (C) Field pole winding. (D) Load current in armature.

Description : In DC generators, armature reaction is produced actually by (A) Its field current. (B) Armature conductors. (C) Field pole winding. (D) Load current in armature.

Last Answer : Ans: D Because load current in armature gives rise to armature mmf which react with main field mmf.

A d.c. shunt motor runs at no load speed of 1140 r.p.m. At full load, armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in r.p.m. is (A) 1080 (B) 1203 (C) 1000 (D) 1200

Description : A d.c. shunt motor runs at no load speed of 1140 r.p.m. At full load, armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in r.p.m. is (A) 1080 (B) 1203 (C) 1000 (D) 1200

Last Answer : (A) 1080

Which of the following methods may be adopted to reduce the effects of armature reaction ? (a) Increase in length of air gap at pole tips (b) Increasing reluctance of pole tips (c) Compensating windings (d) Interpoles (e) All of the above

Description : Which of the following methods may be adopted to reduce the effects of armature reaction ? (a) Increase in length of air gap at pole tips (b) Increasing reluctance of pole tips (c) Compensating windings (d) Interpoles (e) All of the above

Last Answer : (e) All of the above

In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made (a) equal to that of armature mmf (b) less in comparison with the arma¬ture mmf (c) large in comparison with the arma-ture mmf (d) none of the above

Description : In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made (a) equal to that of armature mmf (b) less in comparison with the arma¬ture mmf (c) large in comparison with the arma-ture mmf (d) none of the above

Last Answer : (c) large in comparison with the arma-ture mmf

Define armature reaction in an alternator. Explain the effect of armature reaction at various P.F. of loads of alternator.

Description : Define armature reaction in an alternator. Explain the effect of armature reaction at various P.F. of loads of alternator.

Last Answer : Armature Reaction: The effect of armature flux on main flux is called as armature reaction.  Armature Reaction at Various Power Factors: When armature is loaded, the armature flux modifies ... lagging p.f. For capacitive loads the effect of flux is partly distorting and partly strengthening.

A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction

Description : A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction is  (A) magnetizing (B) demagnetizing (C) cross-magnetizing (D) ineffective

Last Answer : A synchronous generator is feeding a zero power factor (lagging) load at rated current. The armature reaction is demagnetizing 

In a 3 -phase alternator, if there is only magnetizing armature reaction, the load is :

Description : In a 3 -phase alternator, if there is only magnetizing armature reaction, the load is :  (A) capacitive (B) inductive (C) resistive (D) inductive and resistive

Last Answer : In a 3 -phase alternator, if there is only magnetizing armature reaction, the load is : capacitive 

What is the effect of armature reaction?

Description : What is the effect of armature reaction? A) Demagnetization of the main field B) Demagnetization of the brushes C) Cross-magnetization of the brushes D) None of these

Last Answer : What is the effect of armature reaction? A) Demagnetization of the main field B) Demagnetization of the brushes C) Cross-magnetization of the brushes D) None of these

The armature reaction in a synchronous generator supplying leading power factor load is

Description : The armature reaction in a synchronous generator supplying leading power factor load is (A) magnetizing (B) demagnetizing (C) demagnetizing and cross-magnetizing (D) magnetizing and cross-magnetizing

Last Answer : The armature reaction in a synchronous generator supplying leading power factor load is magnetizing and cross-magnetizing

The no load speed of a d.c. shunt motor is 1140 rpm. At full load, the armature reaction weakens the main...

Description : The no load speed of a d.c. shunt motor is 1140 rpm. At full load, the armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in rpm will be: (A) 1080 (B) 1203 (C) 1000 (D) 1200

Last Answer : The no load speed of a d.c. shunt motor is 1140 rpm. At full load, the armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in rpm will be: 1080

In DC generators, armature reaction is produced by the:

Description : In DC generators, armature reaction is produced by the: (A) field current (B) armature conductors (C) field pole winding (D) load current in armature

Last Answer : In DC generators, armature reaction is produced by the: load current in armature

Armature reaction in a generator results in?

Last Answer : Armature reaction in a generator results in demagnetisation of leading pole tip and magnetisation of trailing pole tip.

In a separately excited generator supplying rated load the armature reaction?

Last Answer : In a separately excited generator supplying rated load the armature reaction is always present.

The demagnetising component of armature reaction in a D.C. generator?

Last Answer : The demagnetising component of armature reaction in a D.C. generator reduces generator e.m.f.

Armature reaction of an unsaturated D.C. machine is?

Last Answer : Armature reaction of an unsaturated D.C. machine is crossmagnetising.

What is the effect of motor reaction in a dc generator?

Description : What is the effect of motor reaction in a dc generator?

Last Answer : A force which causes opposition to applied turning force.