What is the meaning of residual magnetism?

What is the meaning of residual magnetism?
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1 Answer

Answer :

Residual magnetism is a property in which certain amount of excitation remains back in the conductor even after the removal of the magnets.
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Related questions

What is residual magnetism?*

Description : What is residual magnetism?*

Last Answer : Magnetism remaining in a Ferro magnetic material after the removal of magnetizing force.

What is residual magnetism? Where is it important?

Description : What is residual magnetism? Where is it important?

Last Answer : Residual magnetism is a property in which certain amount of excitation remains back in the conductor even after the removal of the magnets. It is required as we need some magnetism to start off the generation before the field winding has power to produce the full field.

Indicate which of the following material does not retain magnetism permanently. (a) Soft iron (b) Stainless steel (e) Hardened steel (d) None of the above

Description : Indicate which of the following material does not retain magnetism permanently. (a) Soft iron (b) Stainless steel (e) Hardened steel (d) None of the above

Last Answer : (a) Soft iron

Materials subjected to rapid reversal of magnetism should have (a) large area oiB-H loop (b) high permeability and low hysteresis loss (c) high co-ercivity and high retentivity (d) high co-ercivity and low density

Description : Materials subjected to rapid reversal of magnetism should have (a) large area oiB-H loop (b) high permeability and low hysteresis loss (c) high co-ercivity and high retentivity (d) high co-ercivity and low density

Last Answer : (b) high permeability and low hysteresis loss

Voltage build up in an isolated induction generator depends on A. Capacitor bank value B. Residual magnetism of the rotor iron C. Residual magnetism of the stator iron a) A, B b) A, B, C c) B d) A, C

Description : Voltage build up in an isolated induction generator depends on A. Capacitor bank value B. Residual magnetism of the rotor iron C. Residual magnetism of the stator iron a) A, B b) A, B, C c) B d) A, C

Last Answer : Ans: A

If overloading a DC machine becomes necessary in an emergency, you should ____________. A. cool the machine with portable blowers and fans B. hold thermal overload relays open with blocks of wood C. inject small amounts of CO2 into the windings for cooling D. increase the residual magnetism value of windings to reduce eddy currents

Description : If overloading a DC machine becomes necessary in an emergency, you should ____________. A. cool the machine with portable blowers and fans B. hold thermal overload relays open with blocks of ... the windings for cooling D. increase the residual magnetism value of windings to reduce eddy currents

Last Answer : Answer: A

The insulation of electric generators during short idle periods should be _____________. A. allowed to cool slowly to ambient temperatures B. flashed with direct current to remove any residual magnetism C. kept warm by using strip or space heaters D. relieved of all capacitive charge by grounding the conductors

Description : The insulation of electric generators during short idle periods should be _____________. A. allowed to cool slowly to ambient temperatures B. flashed with direct current to remove any residual ... using strip or space heaters D. relieved of all capacitive charge by grounding the conductors

Last Answer : Answer: C

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

In replacing a defective transformer with a new one, which of the following actions must be carried out to insure proper operation of the equipment it serves? A. The secondary leads must be grounded for 10 minutes to remove static charges. B. The transformer connections must be made as before with regard to the indicated polarity. C. The iron core of the transformer must be flashed to pre-magnetize it. D. The iron core must be grounded for 10 minutes to remove any residual magnetism.

Description : In replacing a defective transformer with a new one, which of the following actions must be carried out to insure proper operation of the equipment it serves? A. The secondary leads must be grounded ... magnetize it. D. The iron core must be grounded for 10 minutes to remove any residual magnetism.

Last Answer : Answer: B

One of the generator bearing shells is generally insulated from the end housing in order to prevent _____________. A. rapid brush wear B. residual magnetism leak off C. excessive field winding heat D. circulation of shaft currents

Description : One of the generator bearing shells is generally insulated from the end housing in order to prevent _____________. A. rapid brush wear B. residual magnetism leak off C. excessive field winding heat D. circulation of shaft currents

Last Answer : Answer: D

Loss of or weak residual magnetism in an alternator or generator can be corrected for by _________________. A. running the rotor in the opposite direction for 5 minutes B. allowing the generator to run at 10% of normal speed for 5 minutes C. running the generator at normal speed with the field rheostat fully counterclockwise D. using a storage battery or battery charger to 'flash' the field

Description : Loss of or weak residual magnetism in an alternator or generator can be corrected for by _________________. A. running the rotor in the opposite direction for 5 minutes B. allowing the generator ... rheostat fully counterclockwise D. using a storage battery or battery charger to 'flash' the field

Last Answer : Answer: D

If a magnetic controller contact fails to pick up when the operating coil is energized, one possible cause may be _______________. A. low spring pressure B. low voltage to the coil C. the residual magnetism of the contact faces D. dirty contact faces

Description : If a magnetic controller contact fails to pick up when the operating coil is energized, one possible cause may be _______________. A. low spring pressure B. low voltage to the coil C. the residual magnetism of the contact faces D. dirty contact faces

Last Answer : Answer: B

Insufficient brush pressure on a DC motor may cause _______. A. generator overload B. excess residual magnetism C. water vapor absorption D. sparking of the brushes

Description : Insufficient brush pressure on a DC motor may cause _______. A. generator overload B. excess residual magnetism C. water vapor absorption D. sparking of the brushes

Last Answer : Answer: D

The greatest detrimental effect on idle electrical equipment, such as cargo pump motors, is the _____________. A. loss of residual magnetism B. absorption of moisture in the insulation C. insulation varnish flaking D. dirt collecting on the windings

Description : The greatest detrimental effect on idle electrical equipment, such as cargo pump motors, is the _____________. A. loss of residual magnetism B. absorption of moisture in the insulation C. insulation varnish flaking D. dirt collecting on the windings

Last Answer : Answer: B

Residual magnetism in steel for magnets is increased by the addition of (A) Nickel (B) Cobalt (C) Tungsten (D) Chromium

Description : Residual magnetism in steel for magnets is increased by the addition of (A) Nickel (B) Cobalt (C) Tungsten (D) Chromium

Last Answer : (B) Cobalt

Addition of __________ to the steel helps in increasing the residual magnetism in steel used for making magnets. (A) Chromium (B) Nickel (C) Tungsten (D) Cobalt

Description : Addition of __________ to the steel helps in increasing the residual magnetism in steel used for making magnets. (A) Chromium (B) Nickel (C) Tungsten (D) Cobalt

Last Answer : (D) Cobalt

The magnetism left in the iron after exciting field has been removed is known as (a) permeance (b) residual magnetism (c) susceptance (d) reluctance

Description : The magnetism left in the iron after exciting field has been removed is known as (a) permeance (b) residual magnetism (c) susceptance (d) reluctance

Last Answer : (b) residual magnetism

If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be?

Description : If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be?

Last Answer : If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be zero.

In D.C. machines the residual magnetism is of the order of?

Last Answer : In D.C. machines the residual magnetism is of the order of 2 to 3 percent.

What is the meaning of a normally open contact?

Description : What is the meaning of a normally open contact?

Last Answer : The contact is open in the normal (de-energised condition).

What is the meaning of excitation in an alternator?

Description : What is the meaning of excitation in an alternator?

Last Answer : An electric generator or electric motor consists of a rotor spinning in a magnetic field. The magnetic field may be produced by permanent magnets or by field coils. In the case of a machine ... rotor. The process of generating a magnetic field by means of an electric current is called excitation.

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Description : What is meaning of short circuit?

Last Answer : A short circuit occurs when conductors are connected (shorted) together by a fault. This is normally phase to phase fault due to failure of insulation by something cutting the wires, fires, etc.

What is the meaning of overload?

Description : What is the meaning of overload?

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What is the meaning of ACB, MCCB, NFB?

Description : What is the meaning of ACB, MCCB, NFB?

Last Answer : Air circuit breaker for 400V higher current ratings. Moulded case circuit breaker for 400V medium current ratings. No Fuse Breaker – 75 A capacity

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Description : What is the meaning of Star winding/ Delta winding?

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Description : What is the meaning of earthing in a ship?

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Description : What is the meaning of saying I and V are in phase?

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Description : What is the meaning of power factor?

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Description : What is the meaning of preferential trip? Why is it provided

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5) An iron ring of mean circumference of 80 cm is uniformly wound with 500 turns of wire. Calculate the value of flux density that a current of 1 A would produce in the ring. Assume relative permeability 1400.

Description : Please ripley me due to emergency

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Can you help me solve my electrical mystery?

Description : Can you help me solve my electrical mystery?

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Description : How to tell if a power strip is burned out?

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Description : I accidently soaked an extension cord. Is it safe to use it again after letting it dry out for awhile?

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How can a solar array power source be bypassed when the batteries run low?

Description : How can a solar array power source be bypassed when the batteries run low?

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Description : How to stop a signal going through a wire?

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Description : Air conditioning will not turn on, is it electrical?

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What is the speaker driving voltage of an amplifier?

Description : What is the speaker driving voltage of an amplifier?

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Description : Why is my Garbage disposal leaking water from the bottom?

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Description : Have you ever taken a shower or bath during an electrical storm?

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