Brushless generators are designed to operate without the use of ___________. A. brushes B. slip rings C. commutators D. all of the above

Brushless generators are designed to operate without the use of ___________. A. brushes B. slip rings C. commutators D. all of the above
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Answer: D  
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Related questions

Which of the following statements is true concerning all three-phase alternators? A. Each has three separate but identical armature windings acted on by one system of rotating magnets. B. Each has one armature winding acted on by three identical but separate systems of rotating magnets. C. All three-phase alternators are designed to operate with a 0.8 leading power factor. D. The three phases always provide power to the load through three sets of slip rings and brushes.

Description : Which of the following statements is true concerning all three-phase alternators? A. Each has three separate but identical armature windings acted on by one system of rotating magnets. B. Each has one ... The three phases always provide power to the load through three sets of slip rings and brushes.

Last Answer : Answer: A

Voltage generated by most AC generators is fed from the machine to the bus by means of ____________. A. brushes on a commutator B. brushes on slip rings C. slip rings on a commutator D. direct connections from the stator

Description : Voltage generated by most AC generators is fed from the machine to the bus by means of ____________. A. brushes on a commutator B. brushes on slip rings C. slip rings on a commutator D. direct connections from the stator

Last Answer : Answer: D

An AC generator operating in parallel loses its excitation without tripping the circuit breaker. This will __________. A. not affect the faulty generator due to the compensation of the other generators B. cause the slip rings to melt C. cause a low voltage differential to develop between the armature and the bus D. cause high currents to be induced in the field windings

Description : An AC generator operating in parallel loses its excitation without tripping the circuit breaker. This will __________. A. not affect the faulty generator due to the compensation of the other generators B. ... between the armature and the bus D. cause high currents to be induced in the field windings

Last Answer : Answer: D

To properly seat the brushes on slip rings, you should use ____________. A. sand paper B. crocus cloth C. emery cloth D. all of the above

Description : To properly seat the brushes on slip rings, you should use ____________. A. sand paper B. crocus cloth C. emery cloth D. all of the above

Last Answer : Answer: A

An alternator will fail to produce line voltage as a result of _____________. A. a closed circuit breaker B. oxidized slip rings C. improperly staggered brushes D. exciter generator failure

Description : An alternator will fail to produce line voltage as a result of _____________. A. a closed circuit breaker B. oxidized slip rings C. improperly staggered brushes D. exciter generator failure

Last Answer : Answer: D

Which of the following statements represents the FIRST step in seating new brushes on slip rings? A. Wrap sandpaper around the slip rings and slide it back and forth between the brushes and the slip rings. B. Press the brushes against the slip ring with a wood block. C. Increase brush pressure and run at no load for 3 to 4 hours. D. Apply seating compound under the brushes and run at no load for 2 hours.

Description : Which of the following statements represents the FIRST step in seating new brushes on slip rings? A. Wrap sandpaper around the slip rings and slide it back and forth between the brushes and the slip rings. B. ... to 4 hours. D. Apply seating compound under the brushes and run at no load for 2 hours.

Last Answer : Answer: A

The reversal of an AC, three-phase, induction motor is accomplished by ______________. A. changing all three motor leads B. reversing the position of the slip rings C. interchanging any two of the three motor leads D. interchanging any two brushes

Description : The reversal of an AC, three-phase, induction motor is accomplished by ______________. A. changing all three motor leads B. reversing the position of the slip rings C. interchanging any two of the three motor leads D. interchanging any two brushes

Last Answer : Answer: C

In actual applications, electrical connections to 'R1-R2' of figure 'A' and to 'R1-R2- R3' of figure 'B' shown in the illustration are made by ______________. EL-0092 A. soldered contacts B. spliced and taped connections C. slip rings and brushes D. solderless crimp-on connectors

Description : In actual applications, electrical connections to 'R1-R2' of figure 'A' and to 'R1-R2- R3' of figure 'B' shown in the illustration are made by ______________. EL-0092 A. soldered contacts B. spliced and taped connections C. slip rings and brushes D. solderless crimp-on connectors

Last Answer : Answer: C

In an AC generator, direct current from a separate source is passed through the windings of the rotor _____________. A. by means of slip rings and brushes B. by means of a commutator C. by means of rotating bar magnet D. to minimize the danger of arc over

Description : In an AC generator, direct current from a separate source is passed through the windings of the rotor _____________. A. by means of slip rings and brushes B. by means of a commutator C. by means of rotating bar magnet D. to minimize the danger of arc over

Last Answer : Answer: A

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

What are the materials used to manufacture the brushes for slip rings of an induction motor?

Description : What are the materials used to manufacture the brushes for slip rings of an induction motor?

Last Answer : A:The slip rings are made of brass and phosphor bronze. The brushes are made of metal graphite which is an alloy of copper and carbon.

The current from the stator of an alternator is taken out to the external load circuit through (A) slip rings. (B) commutator segments. (C) solid connections. (D) carbon brushes.

Description : The current from the stator of an alternator is taken out to the external load circuit through (A) slip rings. (B) commutator segments. (C) solid connections. (D) carbon brushes.

Last Answer : (C) solid connections.

Which of the following are the parts of a DC generator that convert the AC in the armature to DC in the external circuit. Are these parts the: w) field poles x) slip rings and the brushes y) commutator and the brushes z) armature and the core

Description : Which of the following are the parts of a DC generator that convert the AC in the armature to DC in the external circuit. Are these parts the: w) field poles x) slip rings and the brushes y) commutator and the brushes z) armature and the core

Last Answer : ANSWER: Y -- COMMUTATOR AND THE BRUSHES

In D.C. generators, current to the external circuit from armature is given through (a) commutator (b) solid connection (c) slip rings (d) none of above

Description : In D.C. generators, current to the external circuit from armature is given through (a) commutator (b) solid connection (c) slip rings (d) none of above

Last Answer : Ans: a

Modern DC generators are fitted with commutating poles to _____________. A. prevent motorizing B. reduce sparking C. reduce the load on the main poles D. reduce spring pressure on the brushes

Description : Modern DC generators are fitted with commutating poles to _____________. A. prevent motorizing B. reduce sparking C. reduce the load on the main poles D. reduce spring pressure on the brushes

Last Answer : Answer: B

If an AC generator experiences voltage failure, the cause may be _____________. A. an open in the field circuit B. the brushes shifting out of the neutral plane C. excessive locked-rotor current D. a rotating slip ring

Description : If an AC generator experiences voltage failure, the cause may be _____________. A. an open in the field circuit B. the brushes shifting out of the neutral plane C. excessive locked-rotor current D. a rotating slip ring

Last Answer : Answer: A

Chattering of the collector ring brushes on a generator may be remedied by _____________. A. lubricating brush holders B. reinsulating the brushes C. cleaning the collector rings D. increasing length of pigtail

Description : Chattering of the collector ring brushes on a generator may be remedied by _____________. A. lubricating brush holders B. reinsulating the brushes C. cleaning the collector rings D. increasing length of pigtail

Last Answer : Answer: C

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

When an alternator is to remain idle for even a few days _________________. A. lift the brushes and disconnect the pigtails B. insulate the collector rings with strips of cardboard C. energize the heater circuit D. open the equalizing bus disconnect switch

Description : When an alternator is to remain idle for even a few days _________________. A. lift the brushes and disconnect the pigtails B. insulate the collector rings with strips of cardboard C. energize the heater circuit D. open the equalizing bus disconnect switch

Last Answer : Answer: C

A commutator's protective oxide film can be destroyed by _________________. A. periods of low humidity B. very low brush current density C. improper brush grade D. all of the above

Description : A commutator's protective oxide film can be destroyed by _________________. A. periods of low humidity B. very low brush current density C. improper brush grade D. all of the above

Last Answer : Answer: D

The mica used in the commutators of DC machinery is _____________. A. harder than copper B. softer than copper C. the same hardness as the copper D. softer than copper but wears away at a slower rate

Description : The mica used in the commutators of DC machinery is _____________. A. harder than copper B. softer than copper C. the same hardness as the copper D. softer than copper but wears away at a slower rate

Last Answer : Answer: A

Why is it desirable to operate paralleled AC generators at the same power factor? A. Circulating currents are kept to a minimum. B. Field excitation losses are kept to a minimum. C. Generator rotors will have a lesser tendency to hunt. D. Because a power factor increase will decrease kilowatt output.

Description : Why is it desirable to operate paralleled AC generators at the same power factor? A. Circulating currents are kept to a minimum. B. Field excitation losses are kept to a minimum. C. Generator ... will have a lesser tendency to hunt. D. Because a power factor increase will decrease kilowatt output.

Last Answer : Answer: A

The main purpose of an electric space heater installed in a large AC generator is to _____________. A. keep the lube oil warm for quick starting B. prevent moisture from condensing in the windings when the machine is shutdown C. prevent the windings from becoming brittle D. prevent acidic pitting of the slip rings

Description : The main purpose of an electric space heater installed in a large AC generator is to _____________. A. keep the lube oil warm for quick starting B. prevent moisture from condensing in the ... is shutdown C. prevent the windings from becoming brittle D. prevent acidic pitting of the slip rings

Last Answer : Answer: B

Which of the following materials is recommended for finishing the slip rings after grinding or turning? A. grade 00 sandpaper B. canvas wiper C. crocus cloth D. smooth file

Description : Which of the following materials is recommended for finishing the slip rings after grinding or turning? A. grade 00 sandpaper B. canvas wiper C. crocus cloth D. smooth file

Last Answer : Answer: C

A three-phase, squirrel cage, induction motor will run hot due to _____________. A. open stator coils B. high power factor C. dirty or corroded slip rings D. reversed commutating poles

Description : A three-phase, squirrel cage, induction motor will run hot due to _____________. A. open stator coils B. high power factor C. dirty or corroded slip rings D. reversed commutating poles

Last Answer : Answer: A

Routine maintenance of a ship's service alternator should include ______________. A. changing the pedestal bearing insulation yearly B. megger testing of all rectifying diodes C. lubricating excitation slip rings D. periodic cleaning of the air filters or screens

Description : Routine maintenance of a ship's service alternator should include ______________. A. changing the pedestal bearing insulation yearly B. megger testing of all rectifying diodes C. lubricating excitation slip rings D. periodic cleaning of the air filters or screens

Last Answer : Answer: D

The main purpose of an electric space heater installed in a large AC generator is to _____________. A. prevent the windings from becoming brittle B. prevent moisture from condensing in the windings during shutdown C. prevent acidic pitting of the slip rings D. keep the lube oil warm for quick starting

Description : The main purpose of an electric space heater installed in a large AC generator is to _____________. A. prevent the windings from becoming brittle B. prevent moisture from condensing in the windings during ... C. prevent acidic pitting of the slip rings D. keep the lube oil warm for quick starting

Last Answer : Answer: B

Erratic operation of the devices represented in the diagrams shown in the illustration could be traced to ____________. EL-0092 A. improper contact at 'R' slip rings or 'S' connections B. a low three-phase voltage supply C. improper contact at 'S' slip rings or 'R' connections D. a high three-phase voltage supply

Description : Erratic operation of the devices represented in the diagrams shown in the illustration could be traced to ____________. EL-0092 A. improper contact at 'R' slip rings or 'S' connections B. a low three- ... . improper contact at 'S' slip rings or 'R' connections D. a high three-phase voltage supply

Last Answer : Answer: A

A generator has been exposed to water and is being checked for its safe operation. Therefore, it is necessary to _______________. A. check for shorted coils with a growler B. take moisture readings with a hydrometer C. test insulation values with a megger D. ground the commutator, or slip rings and run it at half load for 12 hours

Description : A generator has been exposed to water and is being checked for its safe operation. Therefore, it is necessary to _______________. A. check for shorted coils with a growler B. take moisture readings with a ... a megger D. ground the commutator, or slip rings and run it at half load for 12 hours

Last Answer : Answer: C

Which of the following physical characteristics does a wound-rotor induction motor possess that a squirrel cage motor does not? A. Slip rings B. End rings C. A centrifugal switch D. End plates

Description : Which of the following physical characteristics does a wound-rotor induction motor possess that a squirrel cage motor does not? A. Slip rings B. End rings C. A centrifugal switch D. End plates

Last Answer : Answer: A

While starting a main propulsion synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. This indicates the _____________. A. motor has started properly B. field windings are grounded C. slip rings are dirty D. power transmission cables are grounded

Description : While starting a main propulsion synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. This indicates the _____________. A. motor has started ... field windings are grounded C. slip rings are dirty D. power transmission cables are grounded

Last Answer : Answer: A

What are slip rings?

Description : What are slip rings?

Last Answer : The slip rings are made of copper alloys and are fixed around the shaft insulating it. Through these slip rings and brushes the rotor winding can be connected to external circuits.

What are the routines checks on slip rings?

Description : What are the routines checks on slip rings?

Last Answer : a. Correct mV drops brush to be used. b. Brush tension adjustment. c. Air cleaning to reduce leakage current. d. Brush bedding before use. e. Field polarity change every 6 months. 

On electrical generators one of the bearings is isolated from the bedplate. This insulating block should not be painted and must be kept clean to ___________. A. protect operating personnel from shock B. create an isolated ground for the instrumentation C. allow for the expansion of the generator away from the prime mover as it warms up D. eliminate shaft currents to prevent damaging the bearings

Description : On electrical generators one of the bearings is isolated from the bedplate. This insulating block should not be painted and must be kept clean to ___________. A. protect operating personnel from shock ... the prime mover as it warms up D. eliminate shaft currents to prevent damaging the bearings

Last Answer : Answer: D

You are attempting to parallel two AC generators and the synchroscope pointer stops at a position other than 0° prior to closing the circuit breaker. This indicates ___________. A. the frequency of the incoming machine is the same as the bus frequency B. the incoming machine is in phase with the bus, but the frequency is not the same C. the circuit breaker may be closed after breaker has been reset D. there is an existing cross current between generators

Description : You are attempting to parallel two AC generators and the synchroscope pointer stops at a position other than 0° prior to closing the circuit breaker. This indicates ___________. A. the frequency of ... be closed after breaker has been reset D. there is an existing cross current between generators

Last Answer : Answer: A

Which of the following statements, concerning the general maintenance of a brushless generator, is correct? A. Paint should be applied to insulating surfaces on an annual basis. B. Alcohol should be used to remove dust and grime from windings. C. High pressure air should be used to blow out carbon dust. D. Accessible generator parts should be wiped with a clean dry rag on a periodic basis.

Description : Which of the following statements, concerning the general maintenance of a brushless generator, is correct? A. Paint should be applied to insulating surfaces on an annual basis. B. Alcohol should be used to ... . D. Accessible generator parts should be wiped with a clean dry rag on a periodic basis.

Last Answer : Answer: D

What is brushless DC motor?

Description : What is brushless DC motor?

Last Answer : An inverter fed trapezoidal permanent magnet AC motor drive operating in self-controlled mode is called brushless dc motor.

In D.C. generators, the brushes on commutator remain in contact with conductors which?

Last Answer : In D.C. generators, the brushes on commutator remain in contact with conductors which lie under interpolar region.

State the function of following parts of slip ring induction motor: (i) Slip ring (ii) Fan (iii) Brushes (iv) Frame

Description : State the function of following parts of slip ring induction motor: (i) Slip ring (ii) Fan (iii) Brushes (iv) Frame

Last Answer : Sr. No. Name of part Function 1 Slip ring 1) The rotor winding terminals are permanently connected to the slip rings. 2) Connects external resistance to rotor circuit through ... It provides mechanical support to the entire internal parts of motor. 2) Protects the inner parts.

A four-pole induction motor, operating on three-phase 60 cycle current will operate at approximately ___________. A. 850 RPM B. 1,150 RPM C. 1,750 RPM D. 3,550 RPM

Description : A four-pole induction motor, operating on three-phase 60 cycle current will operate at approximately ___________. A. 850 RPM B. 1,150 RPM C. 1,750 RPM D. 3,550 RPM

Last Answer : Answer: C

Shunt, series, and compound wound motors, are all DC motors designed to operate from _____________. A. constant potential, variable current DC sources B. variable potential, constant current DC sources C. variable potential, variable current DC sources D. constant potential, constant current DC sources

Description : Shunt, series, and compound wound motors, are all DC motors designed to operate from _____________. A. constant potential, variable current DC sources B. variable potential, constant current DC ... C. variable potential, variable current DC sources D. constant potential, constant current DC sources

Last Answer : Answer: A

What is the function of the interpoles installed in DC motors? A. To provide greater torque by strengthening the main field. B. To provide sparkless commutation without having to shift the brushes. C. To limit the production of counter-electromotive force. D. To limit the starting surge current.

Description : What is the function of the interpoles installed in DC motors? A. To provide greater torque by strengthening the main field. B. To provide sparkless commutation without having to shift the brushes. C. To limit the production of counter-electromotive force. D. To limit the starting surge current.

Last Answer : Answer: B

Industrial steam generators operate at a steam capacity of? (rra) 1300 kg/s (rrb) 1000 kg/s (rrc) 500 kg/s ( d) 125 kg/s

Description : Industrial steam generators operate at a steam capacity of? (rra) 1300 kg/s (rrb) 1000 kg/s (rrc) 500 kg/s ( d) 125 kg/s

Last Answer : ( d) 125 kg/s

The subcritical steam generators operate between a pressure ranges of? (rra) 120-160 bar (rrb) 100-110 bar ( c) 130-180 bar (rrd) 140- 200 bar

Description : The subcritical steam generators operate between a pressure ranges of? (rra) 120-160 bar (rrb) 100-110 bar ( c) 130-180 bar (rrd) 140- 200 bar

Last Answer : ( c) 130-180 bar

Give reason: Split rings are used instead of slip rings to construct DC dynamo

Description : Give reason: Split rings are used instead of slip rings to construct DC dynamo

Last Answer : Split rings make the current to flow in the same direction in the external circuit in both cycles.

What is the purpose of the slip rings?

Description : What is the purpose of the slip rings?

Last Answer : To conduct the currents induced in the armature to an external load.

State the function of following parts in Induction motor. (i) Stator (ii) Slip rings

Description : State the function of following parts in Induction motor. (i) Stator (ii) Slip rings

Last Answer : Name of part Function Stator 1) Stator frame supports the core, terminal box and protects the inner parts. 2) Stator core houses stator winding. 3) Stator winding ... ) Provides facility to connect external resistance to rotor circuit through brushes for starting and control.

The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open

Description : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the ... frequency of induced voltage across slip ring is A) 30 Hz B) 70 Hz C) 20 Hz D) 35 Hz

Last Answer : The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the normal direction, The frequency of induced voltage across slip ring is 70 Hz