How moisture entry is prevented into bus duct?

How moisture entry is prevented into bus duct?  
by

1 Answer

Answer :

Silicagel breathers at either end. 
by

Related questions

Why cannot we have cables instead of bus duct in main generator?

Description : Why cannot we have cables instead of bus duct in main generator? 

Last Answer : Very large number of cables in parallel required problems of sealing the terminations. 

Which is better, whether a) Phase segregated bus duct or b) Common bus duct?

Description : Which is better, whether a) Phase segregated bus duct or b) Common bus duct?

Last Answer : Phase segregated bus duct is better, since phase to phase faults are avoided.  

Where fault level is more, whether in generator bus duct or UT bus duct? Why?

Description : Where fault level is more, whether in generator bus duct or UT bus duct? Why?

Last Answer : Fault level is more in UT bus duct. Because the fault currents fed by the both generator and GT adds up within UT bus duct in case there is a fault in UT bus duct. 

Why aluminium bus duct is used?

Description : Why aluminium bus duct is used?

Last Answer : Aluminium is nonmagnetic material. Short circuit forces are less. 

The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts by _____________. A. designing the contacts to open slowly B. directing the arc into an arc chute C. an inverse timed thermal trip for short circuit currents D. instantaneous magnetic trip for overload currents

Description : The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts by _____________. A. designing the contacts to open slowly B. directing the arc into an ... an inverse timed thermal trip for short circuit currents D. instantaneous magnetic trip for overload currents

Last Answer : Answer: B

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 three inches of the deck. C. Power ventilation is to be provided if trickle charging is utilized. D. An exhaust duct is to be provided and led from the top of the locker to the open air.

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.

Last Answer : Answer: D

A diesel driven emergency generator is prevented from being paralleled with the ship's service generators by __________. A. an electrical interlock system B. an automatic paralleling trip switch C. the synchronizing oscilloscope D. the reverse current relay

Description : A diesel driven emergency generator is prevented from being paralleled with the ship's service generators by __________. A. an electrical interlock system B. an automatic paralleling trip switch C. the synchronizing oscilloscope D. the reverse current relay

Last Answer : Answer: A

Why is it a good practice to have the frequency of the incoming alternator adjusted slightly higher than that of the loaded alternator when paralleling two alternators? A. This allows the oncoming machine to accept load immediately. B. This prevents the machine from floating on the line. C. The reverse power relay is prevented from activating. D. All of the above.

Description : Why is it a good practice to have the frequency of the incoming alternator adjusted slightly higher than that of the loaded alternator when paralleling two alternators? A. This allows the oncoming machine to ... line. C. The reverse power relay is prevented from activating. D. All of the above.

Last Answer : Answer: D

A generator is prevented from becoming motorized by the use of a/an _____________. A. overspeed trip B. reverse power relay C. back pressure trip D. governor controls

Description : A generator is prevented from becoming motorized by the use of a/an _____________. A. overspeed trip B. reverse power relay C. back pressure trip D. governor controls

Last Answer : Answer: B

Burning of controller contacts, when opening, is prevented by _____________. A. coating the contact surfaces lightly with petroleum jelly B. magnetic blowout coils C. an overvoltage release D. an overcurrent release

Description : Burning of controller contacts, when opening, is prevented by _____________. A. coating the contact surfaces lightly with petroleum jelly B. magnetic blowout coils C. an overvoltage release D. an overcurrent release

Last Answer : Answer: B

Why auto transfer is prevented if the backup protection is operated?

Description : Why auto transfer is prevented if the backup protection is operated?  

Last Answer : The back up protection is supposed to operate in case of a bus fault. Hence the auto transfer is prevented. 

How carona discharge is prevented in generator insulation?

Description : How carona discharge is prevented in generator insulation?

Last Answer : To prevent carona discharges between insulation and the wall of the slot, the insulation in slot portion is coated with semi conducting varnish. This eliminates the formation of creepage sparks during operation and during HV test. 

Why motoring should be prevented in TG and DG?

Description : Why motoring should be prevented in TG and DG? 

Last Answer : In TG motoring prevented due to the turbine limitation otherwise last stage blade will fails. In DG motoring prevented, because of unburned fuel catches fire in DG. 

Factors on which soil resistance depends: a) depth of the electrode b) moisture c) Nacl d) all the above

Description : Factors on which soil resistance depends: a) depth of the electrode b) moisture c) Nacl d) all the above

Last Answer : Ans: D

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

Electrical failures in motors are caused by the breakdown of insulation, which may be caused by _____________. A. penetration of moisture B. accumulation of dirt C. overheating D. all of the above

Description : Electrical failures in motors are caused by the breakdown of insulation, which may be caused by _____________. A. penetration of moisture B. accumulation of dirt C. overheating D. all of the above

Last Answer : Answer: D

Discoloration of the rotor bars in a squirrel-cage motor is typical evidence of _____________. A. moisture B. overheating C. vibration D. all of the above

Description : Discoloration of the rotor bars in a squirrel-cage motor is typical evidence of _____________. A. moisture B. overheating C. vibration D. all of the above

Last Answer : Answer: B

In the illustration, the component labeled 'G' _________. EL-0031 A. is lined with cardboard to maintain a moisture (electrolyte) barrier between cells B. is a one piece container with compartments for each individual cell C. must be UL approved for shipboard use D. can only contain one cell

Description : In the illustration, the component labeled 'G' _________. EL-0031 A. is lined with cardboard to maintain a moisture (electrolyte) barrier between cells B. is a one piece container with compartments for each individual cell C. must be UL approved for shipboard use D. can only contain one cell

Last Answer : Answer: B

Which of the following procedures should be used to maintain a large electric motor during periods of inactivity? A. A thin layer of air-drying varnish should be applied on the windings. B. Compressed air should be blown over areas where dust is deposited. C. Spraying a solvent periodically to remove carbon dust. D. Space heaters should be used to prevent condensation of moisture.

Description : Which of the following procedures should be used to maintain a large electric motor during periods of inactivity? A. A thin layer of air-drying varnish should be applied on the windings. B. ... periodically to remove carbon dust. D. Space heaters should be used to prevent condensation of moisture.

Last Answer : Answer: D

Moisture absorbed in the windings or condensed on the surface of electrical machinery insulation ________. A. is good for long term preserving since most insulation is organic and contains some amount B. lowers the insulation value and is a common cause of fault grounds in idle machines C. will enhance insulation resistance only if it is fresh water and contains no salt D. reduces the amount of current supplied or drawn by the machine so horsepower is limited

Description : Moisture absorbed in the windings or condensed on the surface of electrical machinery insulation ________. A. is good for long term preserving since most insulation is organic and contains some amount B. ... D. reduces the amount of current supplied or drawn by the machine so horsepower is limited

Last Answer : Answer: B

The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the 'master switch' housing & control panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Description : The purpose of the 'heater resistors' for the winch circuit shown in the illustration is to _______________. EL-0102 A. limit the current in the heater circuit B. dispel moisture in the ' ... panel C. keep the winch brake housing below the dew point D. maintain winch motor operating temperature

Last Answer : Answer: B

Which of the listed devices may be installed on a large diesel-electric alternating current propulsion generator? A. Temperature detector coils inserted in the stator slots for measuring stator temperature. B. A CO2 fire extinguishing system. C. Electric space heaters to prevent condensation of moisture. D. All of the above.

Description : Which of the listed devices may be installed on a large diesel-electric alternating current propulsion generator? A. Temperature detector coils inserted in the stator slots for measuring stator temperature. B. ... . C. Electric space heaters to prevent condensation of moisture. D. All of the above.

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

Before working on an electric cargo winch master switch or controller, you should _____________. A. spray the gasket surface with a solvent B. drain condensate from the box C. open the circuit breaker in the power supply and tag D. heat the switch box to remove any moisture

Description : Before working on an electric cargo winch master switch or controller, you should _____________. A. spray the gasket surface with a solvent B. drain condensate from the box C. open the circuit breaker in the power supply and tag D. heat the switch box to remove any moisture

Last Answer : Answer: C

Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test as the ______________. A. insulation may be damaged B. insulation may be covered with moisture C. armature windings will have a greater number of leakage paths D. larger machines may acquire a charge of static electricity during operation

Description : Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test as the ______________. A. insulation may be damaged ... number of leakage paths D. larger machines may acquire a charge of static electricity during operation

Last Answer : Answer: D

Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test, because the ___________. A. static charge of the machine may give a false reading B. armature will have a greater number of leakage paths C. insulation may be damaged D. insulation may be covered with moisture

Description : Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test, because the ___________. A. static charge of the machine ... number of leakage paths C. insulation may be damaged D. insulation may be covered with moisture

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

Electric strip heaters are used in motor controllers to _____________. A. prevent freezing of movable contacts B. keep the components at their design ambient temperature C. prevent condensation of moisture D. minimize resistance in internal circuits

Description : Electric strip heaters are used in motor controllers to _____________. A. prevent freezing of movable contacts B. keep the components at their design ambient temperature C. prevent condensation of moisture D. minimize resistance in internal circuits

Last Answer : Answer: C

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 silica gel around the commutator. C. Place heat lamps in the motor housings. D. Cover the equipment with a canvas tarpaulin.

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

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

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

Moisture damage, as a result of condensation occurring inside of the cargo winch master switches, can be reduced by __________________. A. installing a light bulb in the pedestal stand B. coating the switch box internals with epoxy sealer C. venting the switch box regularly D. using strip heaters inside the switch box

Description : Moisture damage, as a result of condensation occurring inside of the cargo winch master switches, can be reduced by __________________. A. installing a light bulb in the pedestal stand B. coating the ... epoxy sealer C. venting the switch box regularly D. using strip heaters inside the switch box

Last Answer : Answer: D

Which of the listed devices may be installed on a large turbo-electric alternating current propulsion generator? A. Temperature detector coils inserted in the stator slots for measuring stator temperature. B. A CO2 fire extinguishing system. C. Electric space heaters to prevent condensation of moisture. D. All of the above.

Description : Which of the listed devices may be installed on a large turbo-electric alternating current propulsion generator? A. Temperature detector coils inserted in the stator slots for measuring stator temperature. B. A ... . C. Electric space heaters to prevent condensation of moisture. D. All of the above.

Last Answer : Answer: D

What is the colour of silica gel in dry stage and when saturated with moisture in a breather?

Description : What is the colour of silica gel in dry stage and when saturated with moisture in a breather?

Last Answer : Dry stage – Deep blue Saturated stage – Whitish pink

What is the effect of salt content in moisture on resistivity?

Description : What is the effect of salt content in moisture on resistivity?

Last Answer : The resistivity decreases and the salt content is expressed in percent by weight of the contained moisture. It will be noted that the curve flattens off at about 5% salt content and a further increase in salt content gives little decrease in the soil resistivity. 

What is the effect of moisture content on earth resistivity?

Description : What is the effect of moisture content on earth resistivity?

Last Answer : The moisture content is expressed in percent by weight of dry soil. Dry earth weights about 1440 kg per cubic meter and thus 10% moisture content is equivalent to 144 kg of water per cubic ... is very little affected. Below 20%, the resistivity increases very abruptly with the decrease in moisture.

What are the methods of removing moisture from turbine?

Description : What are the methods of removing moisture from turbine?

Last Answer : a. External method by moisture separator and reheater, which separates the moisture and reheates the steam. b. Internally by stainless steel mesh, which reduces moisture (water particles) to 1%. c. By main steam reheat. 

What is the normal value of moisture content allowed in transformer oil?

Description : What is the normal value of moisture content allowed in transformer oil? 

Last Answer :

What is the colour of silica gel in dry stage and when saturated with moisture in a breather?

Description : What is the colour of silica gel in dry stage and when saturated with moisture in a breather?

Last Answer : Dry stage – Deep blue. Saturated stage – Whitish pink. 

The ‘sheath’ is used in cable to (A) provide strength to the cable. (B) provide proper insulation. (C) prevent the moisture from entering the cable. (D) avoid chances of rust on strands.

Description : The ‘sheath’ is used in cable to (A) provide strength to the cable. (B) provide proper insulation. (C) prevent the moisture from entering the cable. (D) avoid chances of rust on strands.

Last Answer : Ans: A The sheath in underground cable is provided to give mechanical strength.

Which of the following guards the opening of heatopancretic duct into the ducodenum

Description : Which of the following guards the opening of heatopancretic duct into the ducodenum

Last Answer : Which of the following guards the opening of heatopancretic duct into the ducodenum A. Semilunar valve ... C. Pyloric sphincter D. Sphincter of Oddi

Assertion: In humans, the duct of Wirsung from pancreas combines with bile duct before opening into duodenum. Reason: Blockage in the duct of Wirsung

Description : Assertion: In humans, the duct of Wirsung from pancreas combines with bile duct before opening into duodenum. Reason: Blockage in the duct of Wirsung

Last Answer : Assertion: In humans, the duct of Wirsung from pancreas combines with bile duct before ... Wirsung will hamper the endocrine function of pancreas

What Empties secretions into the ejaculatory duct?

Description : What Empties secretions into the ejaculatory duct?

Last Answer : Need answer

The parotid gland: a. contains a fascial sheath which is innervated by second cervical nerve b. receives post-ganglionic parasympathetic nerve from the otic ganglion c. contains a duct which opens into the mouth opposite the upper canine tooth d. is composed of serous acini which contribute to the saliva e. is covered by the massenter

Description : The parotid gland: a. contains a fascial sheath which is innervated by second cervical nerve b. receives post-ganglionic parasympathetic nerve from the otic ganglion c. contains a duct which opens ... . is composed of serous acini which contribute to the saliva e. is covered by the massenter

Last Answer : contains a fascial sheath which is innervated by second cervical nerve

Duct leading from parotid gland and opening into vestibule is (a) Haversian duct (b) Stenson’s duct (c) Wolffian duct (d) infra-orbital duct

Description : Duct leading from parotid gland and opening into vestibule is (a) Haversian duct (b) Stenson’s duct (c) Wolffian duct (d) infra-orbital duct

Last Answer : (c) Wolffian duct

Which of the following guards the opening of hepatopancreatic duct into the duodenum? (a) Pyloric sphincter (b) Sphincter of Oddi (c) Semilunar valve (d) Ileocaecal valve

Description : Which of the following guards the opening of hepatopancreatic duct into the duodenum? (a) Pyloric sphincter (b) Sphincter of Oddi (c) Semilunar valve (d) Ileocaecal valve

Last Answer : (b) Sphincter of Oddi

Assertion: During micturition, urine is prevented from flowing back into the ureters. Reason: Urethral sphincters contract during micturition

Description : Assertion: During micturition, urine is prevented from flowing back into the ureters. Reason: Urethral sphincters contract during micturition

Last Answer : Assertion: During micturition, urine is prevented from flowing back into the ureters. Reason: Urethral ... D. If both Assertion and Reason are false

Which of the following is/are true concerning electric power operated watertight door systems? A. Each motor driven door must use the main bus as its source of power. B. Each distribution panel for the system must be on the lowest level where berthing quarters are located. C. Distribution panels must not be provided with a means of locking in order to permit quick activation of the system. D. Each system must have a separate branch circuit.

Description : Which of the following is/are true concerning electric power operated watertight door systems? A. Each motor driven door must use the main bus as its source of power. B. Each distribution panel for ... to permit quick activation of the system. D. Each system must have a separate branch circuit.

Last Answer : Answer: D