Description : Handheld phase sequence indicators are useful when ________. A. preparing to parallel alternators B. connecting lighting branch circuits C. troubleshooting DC motors D. connecting shore power lines to the ship
Last Answer : Answer: D
Description : When paralleling two alternators the synchronizing lamps grow dim and are totally darkened as the synchroscope pointer approaches the 0° position. This indicates the ____________. A. alternator voltages ... alternator is in phase with the bus voltage D. synchroscope pointer is defective or broken
Last Answer : Answer: C
Description : You are reconnecting a three-phase induction motor to the supply line. To prevent possible damage to the load, due to the wrong direction of rotation, you should ____________. ... supply line phase sequence and motor rotation with appropriate indicators, then connect correspondingly marked leads
Description : An alternator switchboard has a synchroscope and synchronizing lamps. If the synchroscope is broken, which of the steps listed is the most essential before an alternator can be paralleled with the bus? ... D. A portable phase sequence indicator must be used to verify the information from the lamps.
Description : You are paralleling two alternators. The synchronizing lamps grow dim and are totally darkened as the synchroscope pointer approaches the 0° position. This indicates that the ____________. A. alternator ... be closed C. incoming alternator is running too slowly D. synchroscope is defective or broken
Last Answer : Answer: B
Description : When paralleling two alternators, the synchronizing lamps remain lit as the synchroscope pointer approaches the 0°. This indicates the _____________. A. incoming alternator is running too fast B. alternator ... apart C. synchroscope is defective or broken D. alternator power factors are in phase
Description : An AC generator panel is fitted with both synchronizing lamps and a synchroscope. When the synchroscope pointer reaches the noon position, one synchronizing light is bright and the other is dark. This ... sequence is incorrect C. the phase sequence is correct D. the generator breaker may be closed
Description : If the pointer of the synchroscope is rotating in the slow direction when you are preparing to parallel two alternators, the _____________. A. incoming machine is turning faster than the load alternator B ... alternator is ready to split D. incoming machine is beginning to pick up some of the load
Description : When shore power is being connected to a ship in dry dock, _____________. A. the ship's generators are paralleled with the shore power to provide continuous power B. proper phase sequence must be ... 450 volts must be supplied from the shore D. exactly 60 Hz must be provided by the terminal
Description : In replacing a defective transformer with a new one, which of the following actions must be carried out to insure proper operation of the equipment it serves? A. The secondary leads must be grounded ... magnetize it. D. The iron core must be grounded for 10 minutes to remove any residual magnetism.
Description : When two AC generators are being paralleled, the breaker should be closed with the synchroscope pointer rotating in the ____________. A. 'slow' direction, just before the 12 o'clock position B. 'fast' ... just before the 12 o'clock position D. 'slow' direction, just after the 12 o'clock position
Description : The devices labeled 'L' in the illustration are _________. EL-0003 A. load lights indicating that the generator breaker is closed and the generator is supplying power to the main bus B. ... o'clock position the lights are at their dimmest or out indicating the the generators are in phase
Description : When replacing a power transistor fitted with a heat sink in a circuit, a coating of silicone grease is applied between the transistor case and the heat sink. This is done to ____________. A. lubricate ... the heat sink C. aid in the removal of the heat sink D. provide maximum heat transfer
Description : To equalize the power factor of two alternators operating in parallel, the ____________. A. field excitation of both units is adjusted B. governors of both units are adjusted C. phase sequence is altered D. kilowatt load is evenly divided
Last Answer : Answer: A
Description : As shown in the illustration, which of the listed actions of the synchroscope pointer is occurring? EL-0002 A. Revolving slowly in the slow direction. B. Revolving rapidly in the slow direction. C. ... stationary at the 12 o'clock position since the leading edges of the A phases are in phase.
Description : You are attempting to parallel two AC generators, and the synchroscope pointer is revolving fast in the clockwise direction. This indicates that the frequency of the incoming machine is _____________. A. higher ... at any pointer position D. the same as the bus frequency but out of phase with it
Description : You are attempting to parallel two AC generators, and the synchroscope pointer is revolving in the fast direction. This indicates that the frequency of the incoming machine is _____________. A. higher ... the same as the bus frequency and the circuit breaker may be closed at any pointer position
Description : You are attempting to parallel two AC generators and the synchroscope pointer stops at a position other than 0° prior to closing the circuit breaker. This indicates ___________. A. the frequency of ... be closed after breaker has been reset D. there is an existing cross current between generators
Description : You are attempting to parallel two AC generators and the synchroscope pointer is revolving in the slow direction. This indicates that the frequency of the incoming machine is _____________. A. higher than ... same as the bus frequency, and the circuit breaker may be closed at any pointer position
Description : When portable cords are connected to devices such as portable tools, you must eliminate direct tension on the joints or terminal screws. Coast Guard Regulations (46 CFR), allow this to be done by ... the plugs together C. installing a special fitting to eliminate plug separation D. all of the above
Description : Unnecessary and frequent applications of varnish to the generator windings to repair defective insulation will result in ____________. A. heavy coatings of varnish interfering with heat dissipation B. ... of the rectifier assembly D. a built-up of varnish without changing generator operation
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
Description : When replacing component 'B' of the circuit shown in the illustration, it is important to know that ____________. EL-0081 A. it is polarity sensitive and must be inserted as indicated on its ... provide the capacitor's initial charge D. it must match the circuit voltage and component 'C' wattage
Description : What type of maintenance involves isolating equipment troubles and replacing defective parts?
Last Answer : Corrective maintenance.
Description : What will happen if transformer in parallel connection have different phase sequence ?
Last Answer : If the phase sequence is in an incorrect manner, in every cycle each pair of phases will get short-circuited.
Description : In preparing to take insulation resistance readings on a main generator, the windings should be grounded for about 15 minutes prior to the test to _____________. A. allow accurate zeroing of the meter ... the windings D. help the windings to cool to the same temperature as the ground test connection
Description : If overloading a DC machine becomes necessary in an emergency, you should ____________. A. cool the machine with portable blowers and fans B. hold thermal overload relays open with blocks of ... the windings for cooling D. increase the residual magnetism value of windings to reduce eddy currents
Description : When troubleshooting AC motors, a portable growler can be used for locating ____________. A. open field coils B. grounded field coils C. grounded stator coils D. shorted stator coils
Description : In the event of a power failure during cargo loading operations, the movement of an electric powered cargo winch will be stopped by ____________. A. a manual override switch B. the weight of the load on the boom C. a spring set brake D. a hand operated band brake
Description : Which of the synchroscope illustrations depicts the appropriate direction of rotation and position for closing the circuit breaker when paralleling AC generators? EL-0053 A. A B. B C. C D. D
Description : When paralleling two AC generators, the synchroscope selector switch and frequency meter switch should be set up to sense the frequency of the _____________. A. bus B. generator on the line C. oncoming generator D. bus transfer relay
Description : The RPM of an AC generator can be measured with a/an _____________. A. ammeter B. voltmeter C. vibrating reed meter D. synchroscope
Description : You are attempting to parallel two AC generators and the synchroscope pointer stops at a position other than 0°. If you close the circuit breaker at this moment _____________. A. the incoming ... hazardous condition will be created by the incoming machine being at a higher frequency than the bus
Description : You are attempting to parallel two AC generators and the synchroscope pointer is revolving slowly in the fast direction. You should _____________. A. use the governor control switch to adjust the incoming ... the 0° position D. use the field rheostat to adjust the speed of the incoming machine
Description : Why synchroscope method is more better compared to others?
Last Answer : It is very accurate as it doesnot require personal judgement
Description : What is a synchroscope?
Last Answer : Synchroscope is an instrument, which shows the phase relationship of emf of the incoming alternator. It also indicates whether the incoming alternator is running slow or fast.
Description : What is synchroscope?
Last Answer : Synchroscope is an instrument, which shows the phase relationship of emf of the incoming alternator and at the same time it also indicates whether it is running slow or fast. This instrument works on ... too fast when alternator (incoming machine) speed is more and less when alternator is too slow.
Description : Which of the following precautions should be taken when troubleshooting various power circuits using a common solenoid-type mechanical voltage tester (wiggins)? A. Never use this tester on circuits greater ... voltage expected in the circuit in order to prevent damage from an off-scale reading.
Description : Fleming's left hand rule is used to find (a) direction of magnetic field due to current carrying conductor (b) direction of flux in a solenoid (c) direction of force on a current carrying conductor in a magnetic field (d) polarity of a magnetic pole
Last Answer : (c) direction of force on a current carrying conductor in a magnetic 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 component C is the ____________. EL-0033 A. fixed contact B. moving contact C. connection terminal D. trip bar
Description : A ground can be defined as an electrical connection between the wiring of a motor and its ____________. A. shunt field B. circuit breaker C. metal framework D. interpole
Description : A three-phase alternator is developing 300 amps, with a 0.8 power factor, at 450 volts. The true indicated power on the kilowatt meter, located on the main switchboard, will be ____________. A. 133 kw B. 155 kw C. 187 kw D. 212 kw
Description : A three-phase alternator is operating at 450 volts with the switchboard ammeter indicating 300 amps. The kw meter currently indicates 163.6 KW, with a power factor of 0.7. If the power factor increases to 0.8, the KW meter would then read ____________. A. 181.4 KW B. 186.8 KW C. 194.2 KW D. 201.4 KW
Description : The winch shown in the illustration operates in any of the positions with the master switch in the 'lower' direction, but will not 'hoist' in any of the master switch hoist positions. Which of the listed faults ... '2M' in the power circuit may be badly corroded. D. Series relay 'FR' may be open.
Description : A shore power circuit breaker should be closed only _____________. A. when the ship's generators have been directly paralleled to those on shore B. in a shipyard C. if a quick disconnect coupling is used D. when the ship's generators have been removed from the bus
Description : Process of replacing the sequence of lines of codes is known as: a. Expanding die macro b. Expanding tri macro c. Tetra macro d. None of these
Last Answer : a. Expanding die macro
Description : The alarm system for an engine order telegraph uses small selsyn motors attached to the indicators. The alarm sounds when the rotors are _____________. A. in synchronous position, no current is flowing, ... and the relays are open D. not synchronized, current is flowing, and the relays are closed
Description : The devices marked 'T' in the illustration are _____________. EL-0080 A. trouble alarm units whose contacts activate when problems arise either on starting or stopping of the motor B. topping ... contactor parts whose contacts start and stop the defrosting cycle of the compressor driven by the motor
Description : As shown in the illustrations, fine adjustments such as 'weather' and 'turning rate' have no effect on steering stand operation when the 'operation control switch' is in ____________. EL-0097 A. GYRO B. HAND C. NFU D. DIFF