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

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
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Answer: D
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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

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

Sparking at the brushes of a DC propulsion motor can be the result of ____________. A. improper brush pressure B. improper brush seating C. reversed interpole polarity D. all of the above

Description : Sparking at the brushes of a DC propulsion motor can be the result of ____________. A. improper brush pressure B. improper brush seating C. reversed interpole polarity D. all of the above

Last Answer : Answer: D

A three-phase, squirrel cage, induction motor will run hot due to a/an ______________. A. improper brush position B. reversed commutating pole C. shorted stator D. high power factor

Description : A three-phase, squirrel cage, induction motor will run hot due to a/an ______________. A. improper brush position B. reversed commutating pole C. shorted stator D. high power factor

Last Answer : Answer: C

Which oxide film is most protective against corrosion? Why?

Description : Which oxide film is most protective against corrosion? Why?

Last Answer : Non-porous stable oxide film is most protective oxide film. This oxide film is extremely adherent and non-porous (protective). Due to the absence of pores or cracks in the oxide film, it forms barrier for further action and therefore, the rate of corrosion of metal decreases rapidly. 

Write the different types of oxide films formed on the metal surface. Explain the oxide film which is more protective against corrosion.

Description : Write the different types of oxide films formed on the metal surface. Explain the oxide film which is more protective against corrosion.

Last Answer : Types of oxide films 1. Stable porous oxide film 2. Stable non porous oxide film 3. Unstable oxide film 4. Volatile oxide film i) Stable nonporous oxide film ii) Unstable oxide films are protective ... . Example: - Such type of oxide film is formed in the metals like Ag, Au, and Pt.

Name the metal oxide film which is more protective. Explain.

Description : Name the metal oxide film which is more protective. Explain.

Last Answer : Stable -non - porous oxide film.  Explanation: Metals like Al forms Al2O3 whose volume is greater than the volume of metal (Al). An extremely tightly adhering, non- porous oxide layers is ... it forms a barrier for further action and hence the rate of oxidation of metal rapidly decreases. 

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

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

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

Last Answer : Answer: D

A device which can be used to check the calibration of a circuit breaker is a _________________. A. 500 volt megohmmeter B. portable low voltage high current testing unit C. standard digital multimeter D. clamp-on voltmeter

Description : A device which can be used to check the calibration of a circuit breaker is a _________________. A. 500 volt megohmmeter B. portable low voltage high current testing unit C. standard digital multimeter D. clamp-on voltmeter

Last Answer : Answer: B

D.C. propulsion motor brush pressure depends on the brush grade used and in practice is set with a ______________. A. multimeter B. manometer C. spring scale D. compound gauge

Description : D.C. propulsion motor brush pressure depends on the brush grade used and in practice is set with a ______________. A. multimeter B. manometer C. spring scale D. compound gauge

Last Answer : Answer: C

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

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

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

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

Electrical machinery insulation will break down more rapidly due to _________________. A. low loading of motors and generators B. frequent megger testing C. high temperatures and vibration D. high operating frequencies

Description : Electrical machinery insulation will break down more rapidly due to _________________. A. low loading of motors and generators B. frequent megger testing C. high temperatures and vibration D. high operating frequencies

Last Answer : Answer: C

)A very high rise in National Income at current market prices and a low rise at constant prices reveals - (1) the high rate of growth in the economy at the current period (2) the increased production in the current period (3) the improper growth of the economy (4) the high rate of inflation prevailing in the economy

Description : )A very high rise in National Income at current market prices and a low rise at constant prices reveals - (1) the high rate of growth in the economy at the current period (2) the increased ... period (3) the improper growth of the economy (4) the high rate of inflation prevailing in the economy

Last Answer : (3) the improper growth of the economy Explanation: When national output is multiplied by present ruling price, we obtain national income at current prices. On the other hand if the national output is ... not indicate increase in product or output, but is rather due to the rise in price level.

A very high rise in National Income at current market prices and a low rise at constant prices reveals (1) the high rate of growth in the economy at the current period (2) the increased production in the current period (3) the improper growth of the economy (4) the high rate of inflation prevailing in the economy

Description : A very high rise in National Income at current market prices and a low rise at constant prices reveals (1) the high rate of growth in the economy at the current period (2) the increased production ... (3) the improper growth of the economy (4) the high rate of inflation prevailing in the economy 

Last Answer :  the high rate of inflation prevailing in the economy

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

In order to take a current reading with a 'clamp-on' ammeter, the instrument's jaws _________________. A. should remain open B. cannot touch the adjacent conductor C. must be fully closed D. will act as a transformer primary

Description : In order to take a current reading with a 'clamp-on' ammeter, the instrument's jaws _________________. A. should remain open B. cannot touch the adjacent conductor C. must be fully closed D. will act as a transformer primary

Last Answer : Answer: C

Impressed current cathodic protection is used on vessels instead of _________________. A. fire alarm systems B. repeated painting C. sacrificial zincs D. vacuum tube degaussing systems

Description : Impressed current cathodic protection is used on vessels instead of _________________. A. fire alarm systems B. repeated painting C. sacrificial zincs D. vacuum tube degaussing systems

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

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

What phenomenon will result if the glass fiber is exposed to long periods of high humidity? ∙ A. stress fatigue ∙ B. core corrosion ∙ C. stress corrosion ∙ D. cladding corrosion

Description : What phenomenon will result if the glass fiber is exposed to long periods of high humidity? ∙ A. stress fatigue ∙ B. core corrosion ∙ C. stress corrosion ∙ D. cladding corrosion

Last Answer : stress corrosion

What phenomenon will result if the glass fiber is exposed to long periods of high humidity?

Description : What phenomenon will result if the glass fiber is exposed to long periods of high humidity?

Last Answer : stress corrosion

When troubleshooting a motor controller, all indications are that a relay coil should be energized. If there were no magnetic pull, with rated voltage measured across the coil, the most probable cause would be that the _________________. A. coil is open B. control fuse is open C. auxiliary contact in series with the coil is defective D. relay armature is stuck

Description : When troubleshooting a motor controller, all indications are that a relay coil should be energized. If there were no magnetic pull, with rated voltage measured across the coil, the most probable cause ... open C. auxiliary contact in series with the coil is defective D. relay armature is stuck

Last Answer : Answer: A

When troubleshooting a console circuit card suspected of being faulty, first check operating voltages, clean the card and then _________________. A. make sure wired connections and push-on connectors are tight B. test each resistor and capacitor on the card with an ohmmeter C. check the continuity of all printed circuit traces with an ohmmeter D. measure the gain of each transistor or integrated circuit

Description : When troubleshooting a console circuit card suspected of being faulty, first check operating voltages, clean the card and then _________________. A. make sure wired connections and push-on connectors ... circuit traces with an ohmmeter D. measure the gain of each transistor or integrated circuit

Last Answer : Answer: A

Periodic testing of circuit breakers is necessary to assure that a correctly rated and properly installed unit _________________. A. can trip faster as it increases in age B. will continue to provide the original degree of protection C. does not exceed its interrupting capacity D. be able to withstand at least 125% of applied voltage

Description : Periodic testing of circuit breakers is necessary to assure that a correctly rated and properly installed unit _________________. A. can trip faster as it increases in age B. will continue to provide ... not exceed its interrupting capacity D. be able to withstand at least 125% of applied voltage

Last Answer : Answer: B

In D.C. motor construction, commutating windings are wound on _________________. A. opposite main poles B. interpoles C. adjacent main poles D. the rotor core

Description : In D.C. motor construction, commutating windings are wound on _________________. A. opposite main poles B. interpoles C. adjacent main poles D. the rotor core

Last Answer : Answer: B

As shown in the illustration, the D.C. motor's direction of rotation in changed by changing the _________________. EL-0101 A. polarity of the generator field B. direction of three-phase motor rotation C. direction of generator rotation D. polarity of the motor field

Description : As shown in the illustration, the D.C. motor's direction of rotation in changed by changing the _________________. EL-0101 A. polarity of the generator field B. direction of three-phase motor rotation C. direction of generator rotation D. polarity of the motor field

Last Answer : Answer: A

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

When troubleshooting a lead-acid storage battery, a weak or dead cell is best detected by _________________. A. measuring and comparing all cells' specific gravity B. taking an open circuit voltage test of individual cells C. visually inspecting the electrolyte levels of each cell D. taking each cell's temperature with a calibrated mercury thermometer

Description : When troubleshooting a lead-acid storage battery, a weak or dead cell is best detected by _________________. A. measuring and comparing all cells' specific gravity B. taking an open circuit ... electrolyte levels of each cell D. taking each cell's temperature with a calibrated mercury thermometer

Last Answer : Answer: A

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

If Relay #5 changed contact position grounding the 'auto' input to the 'pitch controller module', pitch control would be effected by the _________________. EL-0095 A. pitch feedback potentiometer B. Engine room thrust split potentiometer C. Engine room thrust lever only D. Bridge thrust lever only

Description : If Relay #5 changed contact position grounding the 'auto' input to the 'pitch controller module', pitch control would be effected by the _________________. EL-0095 A. pitch feedback potentiometer B. Engine room thrust split potentiometer C. Engine room thrust lever only D. Bridge thrust lever only

Last Answer : Answer: B

When troubleshooting an electronic circuit, a cold solder joint can be located with the aid of an ohmmeter. Once the problem has been located, you should _________________. A. reheat the circuit in an oven to an even temperature and recheck with an ohmmeter B. reheat the connection with a match and recheck with an ohmmeter C. reheat connection with a soldering tool and recheck with an ohmmeter D. do nothing as this is the normal condition

Description : When troubleshooting an electronic circuit, a cold solder joint can be located with the aid of an ohmmeter. Once the problem has been located, you should _________________. A. reheat the circuit in an ... a soldering tool and recheck with an ohmmeter D. do nothing as this is the normal condition

Last Answer : Answer: C

Aboard ship, a grounded field coil in an AC motor can be determined by using a _________________. A. portable growler B. galvanometer C. visual inspection D. megohmmeter

Description : Aboard ship, a grounded field coil in an AC motor can be determined by using a _________________. A. portable growler B. galvanometer C. visual inspection D. megohmmeter

Last Answer : Answer: D

On an engine throttle control system, the auxiliary control circuits are provided with devices to prevent excessive overtravel of the pilot valve by the synchronous motor. These devices are called _________________. A. overlap sensors B. limit switches C. overtravel relays D. proximity switches

Description : On an engine throttle control system, the auxiliary control circuits are provided with devices to prevent excessive overtravel of the pilot valve by the synchronous motor. These devices are called _________________. A. overlap sensors B. limit switches C. overtravel relays D. proximity switches

Last Answer : Answer: B

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

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

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

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

One of the generator or motor bearings is generally insulated from the end housing in order to prevent ________. A. rapid brush wear B. current leakage from the shaft C. excessive field winding heat D. circulation of shaft currents induced in the machine's frame

Description : One of the generator or motor bearings is generally insulated from the end housing in order to prevent ________. A. rapid brush wear B. current leakage from the shaft C. excessive field winding heat D. circulation of shaft currents induced in the machine's frame

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

What is the medical term for the fetish of slowly peeling protective film off of new products?

Description : What is the medical term for the fetish of slowly peeling protective film off of new products?

Last Answer : There isn’t one. The world is full of things for which we have not invented words.

Function of thinner in a paint is to (A) Accelerate the oxidation of oil (B) Prevent gelling of the paint (C) Suspend pigments & dissolve film forming materials (D) Form a protective film

Description : Function of thinner in a paint is to (A) Accelerate the oxidation of oil (B) Prevent gelling of the paint (C) Suspend pigments & dissolve film forming materials (D) Form a protective film

Last Answer : (C) Suspend pigments & dissolve film forming materials

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

Enzymes are destroyed, when the (A) Temperature is very high (B) Reactant's concentration is very high (C) Reactant's concentration is very low (D) Reaction rate is independent of the reactant's concentration

Description : Enzymes are destroyed, when the (A) Temperature is very high (B) Reactant's concentration is very high (C) Reactant's concentration is very low (D) Reaction rate is independent of the reactant's concentration

Last Answer : (A) Temperature is very high

A major problem in standard carnation production resulting in asymmetrical flowers is: a. Improper fertilization b. High-density spacing c. Calyx splitting d. Lack of pinching

Description : A major problem in standard carnation production resulting in asymmetrical flowers is: a. Improper fertilization b. High-density spacing c. Calyx splitting d. Lack of pinching

Last Answer : Calyx splitting

Which of the following statements describes the significance of ambient temperature in relation to the service life of electronic components? A. Ambient temperature should be as high as possible to drive off moisture. B. Increased ambient temperature decreases the service life of electronic components. C. Ambient temperature is not significant as long as the relative humidity is kept low. D. A reduced ambient temperature causes a corresponding reduced service life.

Description : Which of the following statements describes the significance of ambient temperature in relation to the service life of electronic components? A. Ambient temperature should be as high as possible to drive ... is kept low. D. A reduced ambient temperature causes a corresponding reduced service life.

Last Answer : Answer: B

Drinking of mineral water with very low levels of pesticides (about 0.02 ppm) for long periods may:

Description : Drinking of mineral water with very low levels of pesticides (about 0.02 ppm) for long periods may:

Last Answer : Drinking of mineral water with very low levels of pesticides (about 0.02 ppm) for long ... . cause leukaemia D. Produce immunity against mosquito.

1. The term ‘Butterfly Stroke’ is associated with which game? 2. Which vitamin is very liable and easily destroyed during cooking as well as storage? 3. Who acts as the Chancellor of State Universities ? 4. Which current is produced by upwelling of cold water off the coast of Chile and Peru? 5. By whom was the structure of Qutab Minar was completed?

Description : 1. The term Butterfly Stroke' is associated with which game? 2. Which vitamin is very liable and easily destroyed during cooking as well as storage? 3. Who acts as the Chancellor of State Universities ... scale? 19. Maharashtrian Plateau is made up of which? 20. By whom was Nishat Garden built?

Last Answer : Answer : 1. Swimming 2. Vitamin C 3. Governor 4. Humboldt current 5. Iltutmish 6. Radioactive decay 7. Lewis Caroll 8. P. C. Mahalanobis 9. Australia 10. Bairam Khan 11. Spleen 12. Nagaland 13. Reduces ... 14. Block mountains 15. 1560 16. E. M. Foster 17. Illinois 18. 310 19. Lava 20. Jahangir

In a three-phase electrical system, three ground detecting lamps are provided. If all three lamps REMAIN at half-brilliance when the ground detecting test switch is operated, ______________. A. there is a slight ground on all three phases B. the switch must be replaced C. there are no grounds present D. the light bulbs are of improper voltage

Description : In a three-phase electrical system, three ground detecting lamps are provided. If all three lamps REMAIN at half-brilliance when the ground detecting test switch is operated, ______________. A. there is a ... must be replaced C. there are no grounds present D. the light bulbs are of improper voltage

Last Answer : Answer: C

Prior to taking a resistance reading with a volt-ohm-milliammeter, the 'zero' setting must be adjusted. After clipping the two leads together, you find the adjustment knob will not return the pointer to 'zero'. This is most likely an indication of ______ A. an improper resistance range setting B. weak batteries C. a faulty zero ohms knob D. a faulty meter movement

Description : Prior to taking a resistance reading with a volt-ohm-milliammeter, the 'zero' setting must be adjusted. After clipping the two leads together, you find the adjustment knob will not return the pointer ... range setting B. weak batteries C. a faulty zero ohms knob D. a faulty meter movement

Last Answer : Answer: B