Which of the listed colors properly describes a DC motor commutator when correct commutation is taking place? A. Shiny blue B. Burnished green C. Brick red D. Chocolate brown

1 Answer

Answer :

Answer: D

Related questions

Description : Which of the listed procedures should be carried out to prevent moisture damage to electrical apparatus during extended periods of idleness? A. Fill the motor housing with CO2 to inert the space. B. Strap ... C. Place heat lamps in the motor housings. D. Cover the equipment with a canvas tarpaulin.

Last Answer : Answer: C

Description : If a D.C. motor hums, but does not run when energized, which of the listed conditions could exist? A. Incorrect lead connections B. Incorrect brush setting C. A dirty commutator D. All of the above are correct.

Last Answer : Answer: D

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

Description : Which of the listed conditions will occur if dirt and grease are allowed to accumulate between the commutator segments of a motor? A. A partial short circuit. B. A dead short circuit. C. Misalignment of the motor shaft. D. Overspeeding of the motor.

Last Answer : Answer: A

Description : In general, D.C. propulsion motor brush sparking can be caused by _______________. A. incorrect brush grade, pressure or position B. a concentric commutator C. a dark chocolate colored commutator D. all of the above

Last Answer : Answer: A

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

Description : A short in the shunt field of a DC motor is best located by _____________. A. visual inspection of the commutator B. applying AC voltage to each field coil and measuring the voltage drop across ... using a growler and hacksaw blade D. isolating each coil from the others and using a megohmmeter

Last Answer : Answer: B

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

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

Description : The function of the commutator in a DC motor is to ________. A. reverse the flow of current through the armature B. reverse the flow of current in the field poles C. reduce the reluctance of the magnetic path through the motor D. shift the neutral running plane of the brushes to prevent sparking

Last Answer : Answer: A

Description : Natalie had fourteen balls. Each one color. She alternated the colors each day, there was a blue, pink, purple, green, red, yellow, black, white, orange, turquoise, tan, neon pink, and brown. Each day of the ... the week will she go to Arby's? What ball will she have while she is at Arby's? -Riddles

Last Answer : She will go to Arby's on Monday, for that is the first day of the week and A is the first letter of the alphabet. So on Tuesday she would go to Burger King. On Wednesday she would go to Chick- ... because red is the first color of the rainbow. So on Tuesday she would have a Orange ball. And so on.

Description : Which of the terms listed best describes a compound-wound DC generator having a higher voltage at no load than at full load? A. Flat compounded B. Over compounded C. Under compounded D. Terminal compounded

Last Answer : Answer: C

Description : Which of the listed faults cannot be eliminated, EXCEPT by turning or grinding a commutator with a rigidly supported tool? A. Sparking brushes B. Eccentricity C. High mica D. Blackened commutator

Last Answer : Answer: B

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

Description : Explain the process of commutation in a dc machine. Explain what are inter-poles and why they are required in a dc machine.

Last Answer : Commutation: It is phenomenon when an armature coil moves under the influence of one pole- pair; it carries constant current in one direction. As the coil moves into the influence of the ... region of the main poles and therefore influence the armature coils only when these undergo commutation.

Description : At a local bar, three friends, Mr. Green, Mr. Red and Mr. Blue, were having a drink. One man was wearing a red suit; one a green suit; and the other a blue suit. 'Have you noticed,' said ... looked at the other two and said, 'You're absolutely correct.' What color suit is each man wearing? -Riddles

Last Answer : Since none of the men are wearing the color of suit that corresponds to their names, and Mr. Red was replying to the man in the blue suit, it had to be Mr. Green to whom he replied. We then know ... wearing a blue suit. Therefore, Mr. Red is wearing a green suit and Mr. Blue is wearing a red suit.

Description : Which of the listed electrical devices is represented by the symbol shown in the illustration? EL-0055 A. Fixed resistance resistor B. Coil with magnetic core C. DC motor or generator shunt field D. Transformer

Last Answer : Answer: D

Description : Which of the listed conditions could cause a DC motor to have excessively hot windings and sparking at the brushes? A. Reversed interpole polarity B. High bar-to-bar voltage C. Loose brushes D. Excessive humidity

Last Answer : Answer: A

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

Description : For a DC motor, what major component in addition to the field winding and the armature winding is necessary? w) a commutator x) a stator y) a battery z) a rotor

Last Answer : ANSWER: W -- A COMMUTATOR

Description : State the function of following parts of DC motor : i) Yoke ii) Poles iii) Field winding iv) Commutator. 

Last Answer : Function : i) Yoke: The yoke serves the following two purposes. i) It supports the other components such as poles and provides mechanical protection for whole machine. ii) It forms a part of ... one pole to another and thus to help the motor to develop a continuous and unidirectional torque  

Description : The function of a brush and commutator arrangement in a dc motor is to  (1) produce unidirectional torque (2) produce unidirectional current in the armature (3) help in changing the direction of rotation of the armature (4) reduce sparking

Last Answer : The function of a brush and commutator arrangement in a dc motor is to produce unidirectional torque

Description : Temporary repairs to an open DC propulsion armature coil can be made by _____________. A. connecting the coil ends directly to a pair of negative brushes B. disconnecting coil ends, insulating ... C. grounding the coil ends and short circuiting the commutator bar D. removing the sparking brushes

Last Answer : Answer: B

Description : A shunt-wound DC generator is one in which the shunt field windings are in parallel with the _____________. A. commutator B. brushes C. armature D. all of the above

Last Answer : Answer: D

Description : The purpose of the commutator and brushes on a DC generator is to _____________. A. transfer generated direct current voltage from the armature to the line B. convert the alternating voltage ... contact method to excite the field D. reduce sparking between the armature and the carbon brushes

Last Answer : Answer: B

Description : The endangered species are listed in what colour data book? (1) Black (2) Red (3) Green – (4) Blue

Last Answer : (2) Red Explanation: A Red Data Book contains lists of species whose continued existence is threatened. Species are classified into different categories of perceived risk. Each Red Data Book usually deals with a specific group of animals or plants (e, reptiles, insects, mosses).

Description : The endangered species are listed in what colour data book? (1) Black (2) Red (3) Green (4) Blue

Last Answer : Red

Description : Why are the color printer inks magenta, cyan and yellow and not RGB (red, green, blue, the "primary colors")?

Last Answer : Additive vs subtractive color. Additive - Adding light to black (no light) Shine red, green, and blue spotlights on a wall - where they intersect: Blue + Green = cyan Red + Blue = magenta Red + ... : Additive and Subtractive Colors The Paper Mill Store - CMYK and RGB Color: Which One Should You Use?

Description : How many different colors of red, green, blue and yellow do you know?

Last Answer : Hypocrisy_Central Pssst, I think you forgot to put Boring Question #55: in front of your title…~

Description : Violet, indigo, blue and green, yellow, orange and red; these are the colors you have seen after the storm has fled. What am I? -Riddles

Last Answer : I am a Rainbow.

Description : What scale uses a range of numbers from 6-12 and the colors blue green and red to determine at what level is of exertion you are exercising?

Last Answer : What is the answer ?

Description : What are the primary colors of Pigment? A. White, Black, Blue B. Red, Yellow, Blue (Answer) C. Red, Orange, Blue D. Red, Green, Blue

Last Answer : B. Red, Yellow, Blue (Answer)

Description : What are the primary colors of Light? 33 A. White, Black, Blue B. Red, Yellow, Blue C. Red, Orange, Blue D. Red, Green, Blue (Answer)

Last Answer : D. Red, Green, Blue (Answer)

Description : A cube of side 4cm is painted with 3 colors red, blue and green in such a way that opposite sides are painted in the same color. This cube is now cut into 64 cubes of equal size. ➢ How many ... one side painted. ➢ How many cubes have no side painted. ➢ How many have exactly one side not painted.

Last Answer : Here are the answers. Cubes that have at least two sides painted in different colours are 24 + 8 = 32. Cubes that have only one side painted are 24. Cubes that have no side painted = 8. Cubes that have exactly one side not painted = 0.

Description : A cube of side 4cm is painted with 3 colors red, blue and green in such a way that opposite sides are painted in the same color. This cube is now cut into 64 cubes of equal size. 1. How many ... side painted. 3. How many cubes have no side painted. 4. How many have exactly one side not painted.

Last Answer : Here are the answers. 1. Cubes that have at least two sides painted in different colours are 24 + 8 = 32. 2. Cubes that have only one side painted are 24. 3. Cubes that have no side painted = 8. 4. Cubes that have exactly one side not painted = 0.

Description : Which of the following statements describes what will happen when both the polarity of the field poles, and the direction of current to the brushes of a DC motor are reversed? A. The motor will ... of rotation of the armature will remain the same. D. The field pole windings will become overheated.

Last Answer : Answer: C

Description : If the circuit shown in the illustration were energized and operating properly, which of the devices listed would be open? EL-0007 A. The stop push-button B. The start push-button C. Contact 'Ma' D. Contact 'OL1'

Last Answer : Answer: B

Description : The most practical method used for resurfacing a ship's service motor commutator is to _____________. A. turn it down in the ship's lathe B. use a grinding rig C. use a hand stone D. burnish it with commutator stones

Last Answer : Answer: B

Description : Uneven wear of the commutator surface on a direct current propulsion motor can be caused by _____________. A. rapid change in load B. excessive operation at light load C. incorrect brush staggering D. unequal pole spacing

Last Answer : Answer: C

Description : Sparking at the brushes of a running motor could be an indication of _____________. A. normal operation B. a dirty commutator C. increased brush capacity D. water vapor absorption

Last Answer : Answer: B

Description : The most effective method of locating a loose commutator bar in a D.C. motor is by _____________. A. visual inspection B. jiggling each by hand C. sounding each bar with a light weight hammer D. checking with a calibrated torque wrench

Last Answer : Answer: C

Description : In the illustrated test, if the lamp fails to light on any of the three windings then _________. EL-0027 A. all three windings are grounded and the motor should be sent out for repair B. ... the motor controller and the controller should be checked D. the test should be redone at a higher voltage

Last Answer : Answer: C

Description : D.C. motor brush adjustment includes attention to _________. A. angle with the commutator and clearance within the holder B. brush length and pigtail tightness C. grade of material and surface dirt conditions D. all of the above

Last Answer : Answer: D

Description : In D.C. motor construction, the armature coils' ends are _______________. A. soldered to the commutator bar risers B. imbedded into core slots C. crimped together with brush pigtails D. spliced with the field windings

Last Answer : Answer: A

Description : An important factor in reducing D.C. motor commutator wear is _______________. A. keeping the ambient humidity as low as possible B. ensuring a very low brush current density C. establishing the copper oxide surface film D. all of the above

Last Answer : Answer: C

Description : Basic electrical motor action depends on _______________. A. a conductor rotated within a magnetic field B. a current carrying conductor placed in a magnetic field C. the relative force of the commutator and commutating poles D. the relative force of the armature and interpoles

Last Answer : Answer: B