When the fuse will take over?

1 Answer

Answer :

When the current increases beyond 700% then the fuse will take over from the thermal overload protection.  

Related questions

Description : A circuit breaker and a fuse have a basic similarity in that they both _____________. A. can be reset to energize the circuit B. should open the circuit when overloaded C. will burn out when an over current flow develops D. all of the above

Last Answer : Answer: B

Description : Why AVR changes over to manual on AVR PT fuse failure? 

Last Answer : Because loss of feedback to voltage corrector.  

Description : ACSR (Aluminium Conductor Steel Reinforced) are used as (A) over head transmission lines. (B) super conductors. (C) fuse (D) underground cables.

Last Answer : (A) over head transmission lines.

Description : Booster transformer should never: a) Have fuse in the HV winding b) Be left open circuited c) Be left closed circuited d) None of the above

Last Answer : Ans: B

Description : Which one of the following applications software’s is used to obtain an accurate root locus for? a) LISP b) MATLAB c) dBase d) Oracle Ans: B 6.Lenz devised a rule to find out direction of a)current induced in a circuit b)electromagneticdifference c)potential difference d)flow of power in fuse

Last Answer : Ans: A

Description : When changing fuses, you should always _____________. A. wear rubber boots B. use a fuse puller C. stand on a rubber mat D. wear safety glasses

Last Answer : Answer: B

Description : Which of the following precautions should be taken when a blown fuse, rated at 10 amperes, is replaced? A. Short out the fuse before removing it from the circuit. B. Use needle-nose pliers to ... D. Fuses of 10 ampere rating and less are virtually harmless when energized and may be handled freely.

Last Answer : Answer: C

Description : If a voltage tester is being used to check for defective fuses in the circuit, shown in the illustration, which of the readings will indicate that fuse #2 is open? EL-0062 A. C-B full voltage B. A-D full voltage C. A-D no voltage D. C-B no voltage

Last Answer : Answer: C

Description : If fuse 'F-1' in the illustrated schematic diagram opens, ____________. EL-0017 A. the motor will run slowly B. 'A-1' and 'A-2' will open C. the motor will not start D. the start button will jam in the closed position

Last Answer : Answer: C

Description : In the lighting distribution circuit shown in the illustration, if all switches are closed and fuse 'F2' were to open, all lights on branches ____________. EL-0013 A. '1', '2', and '3' would go out B. '1' ... and '3' would burn dimly D. '1' and '3' would go out, while branch '2' would remain lit

Last Answer : Answer: D

Description : The schematic diagram shown in the illustration uses symbol 'A' to represent a/an _________. EL-0011 A. non-renewable fuse link B. circuit breaker coil C. overload relay coil D. thermal overload heater

Last Answer : Answer: D

Description : In order to safely carry out repairs to a generator circuit breaker, it must be isolated from the bus. This is accomplished by opening the _____________. A. reverse power relay B. bus disconnect link C. generator bus fuse connections D. power directional relay

Last Answer : Answer: B

Description : If fuse #1 shown in the illustration is defective, a voltage tester connected across points 'C' and 'B' will ____________. EL-0062 A. show a reading of 55 volts B. show full line voltage ... C. give positive indication that fuse #2 is good D. give positive indication that fuse #1 is defective

Last Answer : Answer: D

Description : In order to determine whether or not 'fuse 2' shown in the illustration is defective, you should connect the voltage tester leads across points _____________. EL-0062 A. AC B. AD C. BC D. BD

Last Answer : Answer: B

Description : In order to determine whether or not 'Fuse 1', shown in the illustration is defective, you should connect the voltage tester leads across points _____________. EL-0062 A. AC B. AD C. BC D. BD

Last Answer : Answer: C

Description : What is represented by the electric symbol figure 'D' in the illustration? EL-0005 A. Fuse B. Plug-in contact resistor C. Variable capacitor D. Electrolytic capacitor

Last Answer : Answer: A

Description : If an electric motor fails to start, you should FIRST check the _____________. A. phase sequence B. ampere load C. fuse or circuit breaker D. line frequency

Last Answer : Answer: C

Description : When testing for blown fuses in a three-phase supply circuit to a motor, you should first ___________________. A. apply the megger across the tops of the line fuses B. apply an ammeter diagonally across ... of the line fuses D. ensure the circuit is de-energized, and then use a continuity tester

Last Answer : Answer: D

Description : When an AC or a DC motor fails to start, the FIRST step in troubleshooting should be to check the ____________. A. motor windings for obvious opens B. motor controller leads for continuity C. fuse or circuit breaker D. motor controller leads for grounds

Last Answer : Answer: C

Description : In the illustration if BRANCH NO. 1 is a lighting circuit for crew's berthing, Federal Regulations (46 CFR) require the maximum fuse rating for that branch to be _________. EL-0013 A. 80% of the connected load B. 15 amps C. 20 amps D. 30 amps

Last Answer : Answer: C

Description : In the illustrated motor controller, the motor fails to start. A voltmeter reading between 1 and 6 reads line voltage, while the voltmeter reading between 2 and 6 reads 0 VAC. The problem is __________. EL- ... in the 'M' coil, 'Ma' contact/start switch or overload contacts D. fuse '10a' is blown

Last Answer : Answer: B

Description : A circuit with a blown fuse would be described as a/an _____________. A. short circuit B. open circuit C. bonded circuit D. grounded circuit

Last Answer : Answer: B

Description : A fuse will 'blow' if _____________. A. an electric motor is stopped suddenly by opening a switch B. the flow of current to the protection device is reversed C. the electrical current exceeds the rated value of the fuse D. unequal resistors are connected in parallel

Last Answer : Answer: C

Description : In addition to short circuits and sustained overloads, fuses are likely to blow due to _____________. A. loose fuse clips B. low ambient temperatures C. low contact resistance D. all of the above

Last Answer : Answer: A

Description : In the illustration if BRANCH NO. 1 is a lighting circuit for crew's berthing, 46 CFR requires the maximum fuse rating for that branch to be _________. EL-0013 A. 15 amps B. 80% of the connected load C. 20 amps D. 30 amps

Last Answer : Answer: C

Description : Using a fuse whose rating is higher than necessary ________. A. endangers the apparatus it is supposed to protect B. reduces the possibility of short circuits C. increases the efficiency of the equipment by allowing more current to be used D. wastes money because they are more expensive

Last Answer : Answer: A

Description : In the illustration, 'D' is the symbol for a/an __________. EL-0005 A. thermal overload heater B. portable cable C. fuse D. indicating lamp

Last Answer : Answer: C

Description : If a fuse of correct size and type blows frequently, ________________. A. try the next higher amperage rating B. try the next lower amperage rating C. look for trouble within the circuit D. reduce the applied voltage 10%

Last Answer : Answer: C

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

Last Answer : Answer: D

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

Description : When replacing fuses, always make sure _______________. A. to stand on a rubber mat and use rubber gloves B. to use insulated pliers or screwdriver C. the fuse clips are straight, tight, and in good contact D. to increase the fuse rating 10% to guard against 'nuisance blowing'

Last Answer : Answer: C

Description : When troubleshooting motor controllers, a shorted relay or contactor coil is often indicated by _______________. A. a resistance reading of 'infinity' on an ohmmeter B. charred insulation and/or a blown ... of the coil's leads to ground D. a higher-than-normal voltage reading across the winding

Last Answer : Answer: B

Description : You are using a mechanical voltage tester to check the fuses in a three-phase circuit supplying an electric motor. For which of the following reasons must the motor be stopped during the test? A. ... circuit would be indicated by the voltage tester with the circuit energized. D. All of the above.

Last Answer : Answer: B

Description : If the motor fails to start and a voltmeter reading between 1 and 6, as illustrated, indicates line voltage, your next step should be to ________. EL-0007 A. replace fuse '10a' B. replace or repair contact 'Ma' C. reset and determine the cause of the overload D. check line voltage between L1 and L3

Last Answer : Answer: C

Description : An instantaneous-trip-type fuse will _____________. A. open as soon as the load current exceeds its set point B. allow a preset delay between overcurrent and melting C. open a circuit by using a time delay element with a magnetic trip D. reset itself when the overcurrent is corrected

Last Answer : Answer: A

Description : Component 'C' in section 'I' shown in the illustration represent ____________. EL-0093 A. a selectable holding coil arrangement B. a 'fuse blown' indicator circuit C. 'reset' and 'trouble' lamps D. a handset with switch and voice elements

Last Answer : Answer: D

Description : Which of the following conditions is most likely to occur if a single element fuse were used to replace a blown dual element fuse in a motor controller circuit? A. The fuse will blow when the motor ... overheats at high motor loads. C. The motor runs at reduced voltage. D. The motor runs normally.

Last Answer : Answer: A

Description : Before touching a small capacitor connected to a de-energized circuit, or even one that is completely disconnected, you should ____________. A. gently tap the body with a screwdriver B. tag it ... insulated fuse puller D. short circuit the terminals to make sure that the capacitor is discharged

Last Answer : Answer: D

Description : Which of the listed items will stop a motor due to a reduction in voltage and restart it when the voltage is restored to normal? A. Low voltage protection circuit B. Non-renewable link fuse C. Renewable link fuse D. Low voltage release circuit

Last Answer : Answer: D

Description : Since fuse elements are made of zinc or any alloy of tin and lead, the melting point of the fuse element must be _____________. A. higher than that of copper B. lower than that of copper C. equal to that of copper D. reached when the conductor it is protecting becomes 'white hot.'

Last Answer : Answer: B

Description : The part of a fuse that melts and opens the circuit is made of _____________. A. copper and antimony B. steel and babbitt C. aluminum or beryllium alloy D. zinc or an alloy of tin and lead

Last Answer : Answer: D

Description : In a cartridge-type fuse, the metal element is contained in a ___________________. A. porcelain window B. thermal cut out C. fiber tube D. flasher device

Last Answer : Answer: C

Description : A fuse that blows often should be replaced only with a fuse of _____________. A. the recommended current and voltage rating B. higher current and voltage rating C. higher current and lower voltage rating D. lower current and higher voltage rating

Last Answer : Answer: A

Description : A delayed-action fuse is most frequently used in which of the listed circuits? A. Lighting circuit B. Motor circuit C. Electric heater circuit D. Radar circuit

Last Answer : Answer: B

Description : A circuit breaker differs from a fuse in that a circuit breaker _____________. A. melts and must be replaced B. is enclosed in a tube of insulating material with metal ferrules at each end C. gives no visual indication of having opened the circuit D. trips to break the circuit and may be reset

Last Answer : Answer: D

Description : A tubular fuse should always be removed from a fuse panel with _____________. A. a screwdriver B. a pair of insulated metal pliers C. any insulated object D. fuse pullers

Last Answer : Answer: D

Description : Why link is provided in neutral of an ac circuit and fuse in phase of ac circuit?

Last Answer : Link is provided at a Neutral common point in the circuit from which various connections are taken for the individual control circuit and so it is given in a link form to withstand high Amps. ... So if any malfunction happens the fuse connected in the particular control circuit alone will blow off.

Description : Why link is provided in neutral of an ac circuit and fuse in phase of ac circuit?

Last Answer : A:Link is provided at a Neutral common point in the circuit from which various connection are taken for the individual control circuit and so it is given in a link form to withstand high Amps ... .So if any malfunction happen the fuse connected in the particular control circuit alone will blow off.

Description : What is difference between fuse and breaker?

Last Answer : A: (i) Fuse performs both detection and interruption functions. Circuit breaker performs interruption function only. The detection of fault is made by relay system. (ii) The breaking capacity of ... , replacement is required in the fuse. In case of circuit breaker, replacement is not required.

Description : Differentiate between a fuse and a circuit breaker.

Last Answer : Fuse is a low current interrupting device. It is a copper or an aluminium wire. Circuit breaker is a high current interrupting device and it act as a switch under normal operating conditions.