Description : Which of the following problems is indicated if a lead-acid battery begins to gas violently when it is first placed on charge? A. Insufficient compartment ventilation is being provided. B. A short ... undergoing its normal charging rate. D. An excessive charging rate is being applied to the battery.
Last Answer : Answer: D
Description : Violent gassing developed by a lead-acid battery during charging indicates that the ____________. A. plate separators are grounded B. cell voltages are excessive C. specific gravity in insufficient D. charging rate is excessive
Description : Grounds occurring in electrical machinery as a result of insulation failure may result from _____________. A. deterioration through extended use B. excessive heat C. extended periods of vibration D. all of the above
Description : Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? A. Higher than normal operating temperature. B. Excessive vibration at normal speed. C. Sparking at the brushes. D. High megger readings.
Last Answer : Answer: A
Description : On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had dropped out of synchronization with the propulsion generator? A. Excessive ... Tripped main motor interlocks C. Overheated crosstie busses D. Closed contact in the field circuits
Description : Two contributors of electronic console failures are heat and vibration. To combat some of their effects, preventive maintenance procedures should include ______________. A. systematic rotation of circuit cards with those ... bolts and changing of the air in the control room D. all of the above
Last Answer : Answer: B
Description : During the charging process of storage batteries, the charging rooms should be well ventilated because __________. A. without ventilation excessive gassing will occur B. highly poisonous gases are ... gases will otherwise accumulate D. without ventilation the battery will not take a full charge
Last Answer : Answer: C
Description : The pitting of controller contacts can be caused by _____________. A. excessive spring pressure B. insufficient contact pressure C. continuous motor overload D. all of the above
Description : A fuse will blow for all the listed reasons EXCEPT ________. A. excessive vibration B. extremely hot surroundings C. loose fuse clips D. low contact resistance within the fuse
Description : A resistor placed in parallel to the output of a power supply _____________. A. is a temperature compensator B. corrects power factor C. prevents excessive currents D. aids in output voltage regulation
Description : Which of the following statements of Coast Guard Regulations (46 CFR) concerning battery installations is correct? A. Sign, permanently secured to the battery trays, indicating that 'naked lights or smoking is ... on the bottom. D. Power and lighting batteries must be of the lead-acid type only.
Description : Violent gassing from a lead-acid battery while it is being charged, indicates that the _____________. A. plate separators are grounded B. battery compartment ventilation is inadequate C. electrolyte specific gravity is too low D. charging rate is too high
Description : Sodium depletion occurs in excessive sweating, and cannot be corrected by drinking water alone. When uncorrected, it may lead to A. Increase of urea in blood B. Swelling of ankles and feet C. Muscle cramps, loss of energy, fatigue and faintness D. Renal failure
Last Answer : ANSWER: C
Description : Voltage failure of an AC generator may be caused by ____________. A. failure of the exciter generator B. a tripped bus circuit breaker C. high mica segments on the stator bus bar D. excessive prime mover speed
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
Description : Both hydrarch and xerarch successions lead to (a) medium water conditions (b) xeric conditions (c) highly dry conditions (d) excessive wet conditions.
Last Answer : (a) medium water conditions
Description : From the standpoint of safety, you should never allow salt water to enter a leadacid storage battery or come in contact with sulfuric acid because ______________. A. the resulting gas is ... peroxide D. combining salt water with lead-acid creates an invisible gas resulting in severe corrosion
Description : Which of the substances listed should be applied to battery terminals to help prevent corrosion? A. Zinc chromate B. Naval jelly C. Lead peroxide D. Petroleum jelly
Description : A breakable, mercury-filled thermometer should not be used in a lead-acid battery to measure electrolyte temperature, as an accidental breakage can cause ____________. A. severe sparking and explosions ... battery plates C. violent gassing at the positive plates D. corrosion on the battery terminals
Description : Which of the following methods should be used to test for an 'open' coil in an AC motor stator? A. Test with an ohmmeter, one test lead on the shaft, and the other test lead to the stator leads ... an open coil. D. Use a growler, listening for noise and vibration to increase when over an open coil.
Description : Engineering disaster is simply referred to those disasters when it is caused by an engineering failure like – (a) Design flaws or materials failures (b) Insufficient knowledge or underestimations (c) Carelessness or negligence (d) All the above.
Last Answer : (d) All the above.
Description : A partial denture that seats on the master cast but fails to seat correctly in the mouth is a result of, A. Contraction of the metal framework during casting B. Insufficient expansion of the investment material C. Distortion of impression D. Failure to block out unwanted undercuts
Last Answer : C. Distortion of impression
Description : In the illustrated motor controller circuit, which statment is true? EL-0023 A. The high and low speed lights operate at less than line voltage with a resistor in series. B. This controller can be ... . The wattage of the high speed light must be greater than the wattage of the low speed light.
Description : In troubleshooting a circuit in a console, you find that a resistor may be faulty. Which of the precautions listed must be observed when using an ohmmeter to carry out this test? A. Correct polarity ... D. The resistor's circuit must be de-energized and at least one end of the component isolated.
Description : Due to which of the following factors the brush wear rate is altered ? (a) Speed of the machine (b) Contact pressure (c) Surface conditions of brush and commutator (d) Excessive sparking (e) All of the above
Last Answer : Ans: E
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
Description : When charging lead-acid batteries, you should reduce the charging rate as the battery nears its full charge capacity to ______________. A. prevent excessive gassing and overheating B. allow equalization of cell voltages C. reduce lead sulfate deposits D. increase lead peroxide formation
Description : The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50°C in industrial practice mainly to avoid (A) Its evaporation loss (B) Excessive corrosion (C) Uneconomic LMTD (D) Decrease in heat exchanger efficiency
Last Answer : (B) Excessive corrosion
Description : The rotating shaft or rotor vibrates with excessive lateral vibration at angular speed at which occurs is called as A) rotating speed B) critical speed C) vibrating speed D) None of the above
Last Answer : B) critical speed
Description : Consider the following statements: Air vessels are fitted on the suction and delivery sides of a reciprocating pump to 1. Achieve higher speed without separation. 2. Reduce work in overcoming frictional resistance. 3. Avoid excessive vibration ... 2 & 3 only (c) 2, 3 & 4 only (d) 1, 2, 3 & 4
Last Answer : (d) 1, 2, 3 & 4
Description : What is the remedy for a bent steam turbine shaft causing excessive vibration?
Last Answer : 1. The run-out of the shaft near the center as well as the shaft extension should be checked. 2. If the run-out is excessive, the shaft is to be replaced.
Description : What are the possible causes of excessive vibration or noise in a steam turbine?
Last Answer : 1. Misalignment. 2. Worn bearings. 3. Worn coupling to driven machine. 4. Unbalanced coupling to driven machine. 5. Unbalanced wheel. 6. Piping strain. 7. Bent shaft.
Description : How will you detect that misalignment is the probable cause of excessive vibration?
Last Answer : 1. Coupling to the driven machine is to be disconnected. 2. The turbine is to be run alone. 3. If the turbine runs smoothly, either misalignment, worn coupling or the driven equipment is the cause of the trouble.
Description : How can problems of "excessive vibration or noise" due to piping strain be avoided on steam turbines?
Last Answer : 1. The inlet as well as exhaust steam lines should be firmly supported to avoid strains from being imposed on the turbine. 2. Adequate allowance should be made for expansion of steam pipes due to heat.
Description : The disease of dry rot in timber is caused by (A) Lack of ventilation (B) Alternate wet and dry conditions (C) Complete submergence in water (D) None of the above
Last Answer : Answer: Option A
Description : A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by (A) Decreasing the size of the inlet pipe (B) Increasing the size of the inlet pipe (C) Lowering the pump position (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be __________ litres. (A) 448 (B) 224 (C) 22.4 (D) Data insufficient; can't be computed
Last Answer : (A) 448
Description : Which of the listed safety features should be provided in small rooms or lockers where batteries are stored? A. Installation of a fixed CO2 system. B. An exhaust duct is to be provided and led from within ... An exhaust duct is to be provided and led from the top of the locker to the open air.
Description : If a DC motor runs hot, the cause may be _____________. A. high mica condition B. low ambient temperature C. clogged ventilation ducts D. an open in the shunt field
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
Description : In the illustration, the purpose of part B is to _________. EL-0033 A. increase resistance in series with the contacts as they close to prevent arcing B. create a magnetic field in the steel ... event of an overload D. provide ventilation to the contact when the breaker is close to rated capacity
Description : Regarding battery charging rooms, ventilation should be provided __________. A. at the lowest point of the room B. horizontally near the batteries C. at the highest point of the room D. only when charging is in progress
Description : Which of the listed precautions should be observed before spraying liquid solvent on the insulation of an electric motor? A. Slow the motor down to low speed. B. Disconnect the motor from the power source. C. Secure all ventilation in the area. D. Preheat the insulation to assist in cleaning.
Description : What is represented by the two parallel lines within component 'A' of the circuit shown in the illustration? EL-0081 A. A ground connection B. An iron core C. Ventilation openings D. A mounting base
Description : Discuss how the ventilation and cooling of large high speed alternator is carried out.
Last Answer : For high speed alternator two cooling methods are available and they are conventional cooling and direct cooling. In conventional cooling methods, radial and axial ventilating ducts are provided in the ... oil or hydrogen are circulated in the ducts to remove the heat directly from the conductors.
Description : Why ventilation is essential for Ni-Cad also?
Last Answer : Gases evolved H2 O2 can form explosive mixture.
Description : _____ is a surface fatigue failure which occurs when the load on the bearing part exceeds the surface endurance strength of the material. (a) Scoring (b) Pitting (c) Corrosion
Last Answer : (b) Pitting
Description : The short circuit in any winding of the transformer is the result of (a) mechanical vibration (b) insulation failure (c) loose connection (d) impulse voltage
Last Answer : (d) impulse voltage
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
Description : Metabolic alkalosis can occur in (A) Severe diarrhoea (B) Renal failure (C) Recurrent vomiting (D) Excessive use of carbonic anhydrase inhibitors
Last Answer : Answer : C