What are the remedies for armature reaction?

What are the remedies for armature reaction? 
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1 Answer

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. Pole shoes have to modify at trailing pole tip side to increase the reluctance.

d. Pole shoes have to modify to increase the reluctance.

e. In big machines there is chance of load fluctuation, a compensating winding to be

placed at the pole shoes and it is connected in series with the armature winding

such that the current in that winding is opposite to the armature winding.
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Related questions

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

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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

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Last Answer : Answer: C

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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

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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.

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Description : What is meant by armature reaction in Alternators?

Last Answer : The effect of armature flux on main flux

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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.  

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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. 

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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.

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Description : Moving the rheostat handle shown in the illustration, that is used to control a DC generator, towards the 'raise' direction will increase the _____________. EL-0030 A. field resistance B. armature resistance C. armature speed D. line voltage

Last Answer : Answer: D

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Which of the following losses is/are present in every direct current generator armature? A. Winding copper loss B. Core eddy current loss C. Magnetic hysteresis loss D. All of the above.

Description : Which of the following losses is/are present in every direct current generator armature? A. Winding copper loss B. Core eddy current loss C. Magnetic hysteresis loss D. All of the above.

Last Answer : Answer: D

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Description : Three factors responsible for the change in voltage as load is applied to an AC generator are: 1) the drop in resistance in the armature circuit, 2) the change in flux, and 3) the ____________. A. armature winding speed B. inductance load drop C. coil pitch factor D. armature reactance voltage drop

Last Answer : Answer: D

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Description : Hysteresis in a direct current generator is indicated by _____________. A. arcing at the brushes B. pulsating terminal current C. heating of the armature core D. hunting and over control

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Last Answer : Answer: D

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Last Answer : Answer: A

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Description : A series wound DC motor has its armature and field connected in series with a resistor. When the motor is disconnected from its power supply, this motor will exemplify __________. A. the ... the proper connections for an automatic strip heater C. a reversing controller circuit D. dynamic braking

Last Answer : Answer: D

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Description : If the connections for the field and the armature on a DC motor are reversed, _____________. A. the motor will run as a generator B. the motor will not run C. the direction of rotation will be the same D. the direction of rotation will be reversed

Last Answer : Answer: C

Brushes in a generator must be positioned in the neutral plane to avoid sparking between the brushes and the _____________. A. yoke B. armature windings C. field pole windings D. commutator

Description : Brushes in a generator must be positioned in the neutral plane to avoid sparking between the brushes and the _____________. A. yoke B. armature windings C. field pole windings D. commutator

Last Answer : Answer: D

Damp armature windings in a D.C. motor may lead to ____________. A. reduced voltage B. reduced current C. increased resistance D. overheating

Description : Damp armature windings in a D.C. motor may lead to ____________. A. reduced voltage B. reduced current C. increased resistance D. overheating

Last Answer : Answer: D

Which of the listed conditions might contribute to very rapid wearing of a DC machine's commutator bars? A. A grounded commutator bar B. Using improper carbon brushes C. Aligning the front and rear mica V-rings improperly D. An open circuit in the armature

Description : Which of the listed conditions might contribute to very rapid wearing of a DC machine's commutator bars? A. A grounded commutator bar B. Using improper carbon brushes C. Aligning the front and rear mica V-rings improperly D. An open circuit in the armature

Last Answer : Answer: B

If a DC motor runs faster than designed, with all other conditions being normal, the possible cause could be a/an ______________. A. shorted shunt field coil B. open armature coil C. reversed commutating pole D. overload

Description : If a DC motor runs faster than designed, with all other conditions being normal, the possible cause could be a/an ______________. A. shorted shunt field coil B. open armature coil C. reversed commutating pole D. overload

Last Answer : Answer: A

A shorted armature coil in a DC motor can be detected by _____________. A. sparking at the brushes B. shiny armature coil C. worn grooves in the armature D. undercut mica

Description : A shorted armature coil in a DC motor can be detected by _____________. A. sparking at the brushes B. shiny armature coil C. worn grooves in the armature D. undercut mica

Last Answer : Answer: A

An open in the armature of a DC motor is suspected, but is not found by visual inspection of the commutator. The next step in troubleshooting this problem is to ________________. A. conduct a bar to bar test of the armature B. visually inspect the armature windings C. conduct an insulation resistance test of the armature D. test the commutator for a ground

Description : An open in the armature of a DC motor is suspected, but is not found by visual inspection of the commutator. The next step in troubleshooting this problem is to ________________. A. conduct a ... windings C. conduct an insulation resistance test of the armature D. test the commutator for a ground

Last Answer : Answer: A

An open armature connection in a DC propulsion motor could be caused by ____________. A. low-load operation B. clogged ventilation ducts C. sparking at the brushes D. a grounded shunt field coil

Description : An open armature connection in a DC propulsion motor could be caused by ____________. A. low-load operation B. clogged ventilation ducts C. sparking at the brushes D. a grounded shunt field coil

Last Answer : Answer: B

DC generator voltage is decreased by cutting _____________. A. in field resistance B. out field resistance C. in armature resistance D. out armature resistance

Description : DC generator voltage is decreased by cutting _____________. A. in field resistance B. out field resistance C. in armature resistance D. out armature resistance

Last Answer : Answer: A

Which of the methods listed is used to start a AC generator turning? A. Residual magnetism remaining in the field poles. B. Residual magnetism remaining in the field coils. C. Residual magnetism remaining in the armature. D. Rotation by a mechanical prime mover.

Description : Which of the methods listed is used to start a AC generator turning? A. Residual magnetism remaining in the field poles. B. Residual magnetism remaining in the field coils. C. Residual magnetism remaining in the armature. D. Rotation by a mechanical prime mover.

Last Answer : Answer: D

A short circuit in the armature of a DC motor will cause the motor to _____________. A. run fast B. hum when energized C. spark at the brushes D. fail to start

Description : A short circuit in the armature of a DC motor will cause the motor to _____________. A. run fast B. hum when energized C. spark at the brushes D. fail to start

Last Answer : Answer: C

Which of the listed conditions will occur if the polarity of the field poles and the direction of current to the brushes of a DC motor were both reversed? A. The motor would not start. B. The direction of rotation of the armature would be reversed. C. The direction of rotation of the armature would be unchanged. D. The field pole windings would become overheated.

Description : Which of the listed conditions will occur if the polarity of the field poles and the direction of current to the brushes of a DC motor were both reversed? A. The motor would not start. ... direction of rotation of the armature would be unchanged. D. The field pole windings would become overheated.

Last Answer : Answer: C

Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Last Answer : Answer: D

The electrical device shown in the illustration is a/an _____________. EL-0077 A. operating coil B. indicating lamp C. motor armature D. potentiometer

Description : The electrical device shown in the illustration is a/an _____________. EL-0077 A. operating coil B. indicating lamp C. motor armature D. potentiometer

Last Answer : Answer: D

A DC generator is used to supply direct current in order to maintain an AC generator field and is known as a/an _____________. A. rotor B. stator C. exciter D. armature

Description : A DC generator is used to supply direct current in order to maintain an AC generator field and is known as a/an _____________. A. rotor B. stator C. exciter D. armature

Last Answer : Answer: C

The advantage(s) of the method of D.C. motor speed control shown in the illustration is/are ______________. EL-0101 A. elimination of armature starting resistor losses B. elimination of speed instability with variable loads C. the ease of reversing motor direction D. all of the above

Description : The advantage(s) of the method of D.C. motor speed control shown in the illustration is/are ______________. EL-0101 A. elimination of armature starting resistor losses B. elimination of speed instability with variable loads C. the ease of reversing motor direction D. all of the above

Last Answer : Answer: D

A flickering ground detection lamp on a DC system would indicate a _____________. A. multiple-ground condition in the distribution system B. ground in an armature coil of an operating machine C. ground in a motor accompanied with a short D. short between two adjacent bars of the generator commutator

Description : A flickering ground detection lamp on a DC system would indicate a _____________. A. multiple-ground condition in the distribution system B. ground in an armature coil of an operating machine C. ground in a motor accompanied with a short D. short between two adjacent bars of the generator commutator

Last Answer : Answer: B

The basic type of D.C. motor speed control where a generator armature directly feeds the motor armature and the motor and generator fields are excited by a separate D.C. source is called ___________________. A. Burmeister-Wain B. Ward-Leonard C. Sperry-Rand D. Atlas-Copco

Description : The basic type of D.C. motor speed control where a generator armature directly feeds the motor armature and the motor and generator fields are excited by a separate D.C. source is called ___________________. A. Burmeister-Wain B. Ward-Leonard C. Sperry-Rand D. Atlas-Copco

Last Answer : Answer: B

In order to prevent the winch shown in the illustration from turning while troubleshooting the controller circuit, _________________. EL-0102 A. set the dynamic brake by clamping contact 'DB' closed B. set the mechanical brake by the jackscrew provided C. disconnect the brake solenoid at 'B1' and 'B2' D. open the test link preventing current flow to the armature

Description : In order to prevent the winch shown in the illustration from turning while troubleshooting the controller circuit, _________________. EL-0102 A. set the dynamic brake by clamping contact 'DB' closed B. set the ... at 'B1' and 'B2' D. open the test link preventing current flow to the armature

Last Answer : Answer: D

The direction of rotation of the winch shown in the illustration is changed by reversing the _____________. EL-0102 A. direction of current through the shunt field B. polarity of voltage at 'S1' and 'S2' C. direction of current through the armature D. polarity of voltage at 'L1' and 'L2'

Description : The direction of rotation of the winch shown in the illustration is changed by reversing the _____________. EL-0102 A. direction of current through the shunt field B. polarity of voltage at 'S1' and 'S2' C. direction of current through the armature D. polarity of voltage at 'L1' and 'L2'

Last Answer : Answer: C

In addition to undercutting the mica, proper maintenance of a D.C. motor's commutator includes _______________. A. side-cutting the copper segments and insulating the slots B. coating the copper surface with light machine oil for the first four hours of operation C. baking the armature in an oven at a maximum of 95°C for not over 8 hours D. all of the above

Description : In addition to undercutting the mica, proper maintenance of a D.C. motor's commutator includes _______________. A. side-cutting the copper segments and insulating the slots B. coating the copper surface with light machine ... in an oven at a maximum of 95°C for not over 8 hours D. all of the above

Last Answer : Answer: A

In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction motor C. is the armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor

Description : In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction ... armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor

Last Answer : Answer: B

The air gap in an induction motor should be checked periodically with a feeler gage to detect ____________. A. rotor contact with the laminations B. changes in armature magnetic strength C. excessive bearing wear D. electrical damage to the rotor

Description : The air gap in an induction motor should be checked periodically with a feeler gage to detect ____________. A. rotor contact with the laminations B. changes in armature magnetic strength C. excessive bearing wear D. electrical damage to the rotor

Last Answer : Answer: C

The purpose of resistor bank 'R1-R5' in the winch circuit shown in the illustration is to ______________. EL-0102 A. limit armature current in lower and 'series field' current in hoist to obtain required speeds B. divert shunt field current for speed control in both directions of operation C. limit armature current in hoist and 'series field' current in lower to obtain required speeds D. regulate the strength of the brake solenoid 'B1-B2' in both directions of operation

Description : The purpose of resistor bank 'R1-R5' in the winch circuit shown in the illustration is to ______________. EL-0102 A. limit armature current in lower and 'series field' current in hoist to ... required speeds D. regulate the strength of the brake solenoid 'B1-B2' in both directions of operation

Last Answer : Answer: C