Description : The type of control circuit that will not permit automatic restarting after power is restored, following a power failure is called _____________. A. low voltage protection B. low voltage release C. overload lockout D. reduced voltage restart
Last Answer : Answer: A
Description : Where automatic restart does not present a hazard after a power failure, Coast Guard Regulations (46 CFR) require motor controllers for auxiliaries vital to the propelling equipment to be provided ... overload protection B. low voltage protection C. low voltage release D. reverse current protection
Last Answer : Answer: C
Description : A low-voltage protection circuit is used in electric motor starting equipment to _____________. A. trip circuit contactors when the motor overspeeds due to low voltage B. trip circuit ... voltage without manually resetting D. prevent the motor from restarting automatically on restoration of voltage
Last Answer : Answer: D
Description : The type of feature afforded auxiliaries vital to the operation of propelling equipment, where automatic restart after a voltage failure would not create a hazard, is termed _____________. A. low voltage protection B. high amperage protection C. low voltage release D. high amperage release
Description : The illustrated motor controller _________. EL-0023 A. is a low voltage release controller because the motor will stop when voltage falls below a certain value and automaticly start when normal voltage ... with a generator or transformer bank that is 'wye' wound with T2 connected to the neutral
Last Answer : Answer: B
Description : Low voltage releases as used in some shipboard motor starter and control equipment will have which of the following characteristics? A. They trip circuit contactors when the motor starts to overspeed. B. ... coil of the starter. D. They allow the motor to restart upon restoration of normal voltage.
Description : The purpose of a motor undervoltage protection device is to _____________. A. prevent high armature current when power is restored B. start the motor at a very low voltage C. trip the load off the motor in case of fire D. protect personnel from low voltage shocks
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
Description : As shown in the illustration, which of the following conditions will occur as a result of a momentary loss of power? EL-0017 A. The motor will automatically restart when power is restored. B. 'H-4' will open, ... the motor. D. 'A-1' or 'A-2' will open, necessitating a manual restarting of the motor.
Description : When power is restored after a complete power failure, a steering gear pump motor will ____________. A. have to be restarted B. have to be reset C. restart automatically D. trip its overload relays
Description : The wiring diagram for the motor starting circuit shown in the illustration indicates ______________. EL-0007 A. resistance starting B. reduced voltage starting C. low voltage protection D. low voltage release
Description : The main difference between a motor control circuit containing low voltage protection and low voltage release is that the latter contains _____________. A. a magnetic operating coil B. normally open line contacts C. thermal-overload protection D. a momentary-contact start button
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
Description : Two paralleled alternators are operating near rated load. If one trips out mechanically, which of the listed actions should be taken FIRST? A. Restart the tripped machine immediately. B. Strip the board ... circuits. C. Start the emergency generator. D. Transfer all vital loads to the emergency bus.
Description : Which of the following is the least expensive protection for overcurrent is low voltage system ? (a) Rewireable fuse (b) Isolator (c) Oil circuit breaker (d) Air break circuit breaker (e) None of the above
Last Answer : (a) Rewireable fuse
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
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
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.
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.
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
Description : What operational characteristics do the components labeled as 'S' and 'R' represent in the motor controller diagram shown in the illustration? EL-0080 A. Standard and Reverse directions B. Stop and Restart features C. Subnormal and Regular loading D. Start and Run functions
Description : The 'reset' contacts of the master switch shown in the illustration provides the winch controller with ___________. EL-0102 A. low voltage release B. overload protection C. low voltage protection D. high power factor correction
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
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 : A fuse in a motor circuit provides protection against short-circuit and overload.
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
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.
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.
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. ... Supply is on than due to open or break Neutral Voltage is increase and equipment may be damage.
Description : Diesel generators #1 and #2 are operating in parallel at near full load capacity. Diesel generator #1 suddenly trips out mechanically due to low lube oil pressure. The reverse power relay functions ... all nonvital circuits. D. Secure alarms, reset reverse power relay, and restart #1 engine.
Description : If a unloaded shunt motor's field were weakened by rheostat resistance or by an open circuit, the motor would _________. A. overspeed due to reduced CEMF B. stop because of low flux C. continue to run at base speed D. slow down and overheat
Description : Angiotensin converting enzyme inhibitors afford maximum protection against progression of heart failure when used: A. At the higher therapeutic dose range over long term B. At the maximum tolerated dose only till ... restored C. At low doses over long term D. At low doses along with diuretics/digoxi
Last Answer : A. At the higher therapeutic dose range over long term
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 : Protection against sustained overloads occurring in molded-case circuit breakers is provided by a/an __________. A. overvoltage release B. thermal acting trip C. thermal overload relay D. current overload relay
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
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
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
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
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.
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
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%
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 : An increase in which of the listed conditions will increase the speed of a synchronous motor? A. Frequency B. Voltage C. Armature current D. Inductance
Description : If power were lost to the winch shown in the illustration while in 'second point hoist' the winch would stop. When power is restored the winch would ______________. EL-0102 A. continue to run at ' ... switch' is returned to 'off' closing the 'reset' contacts and then moved to any 'run' position
Description : Which of the following actions must be carried out before a voltage tester can be used to test the three line fuses to a three-phase motor? A. The fuses must be removed from the circuit. B. The ... disconnected and tagged. D. Nothing need be done as long as the motor is running under a light load.
Description : Which of the listed conditions will occur if dirt and grease are allowed to accumulate between the commutator segments of a motor? A. A partial short circuit. B. A dead short circuit. C. Misalignment of the motor shaft. D. Overspeeding of the motor.
Description : Which of the listed precautions should be taken when cleaning the internals of a motor with compressed air? A. Open the machine on both ends so as to allow the air and dust to escape. B. Be certain that the ... panel. C. Be certain that the air is clean and as dry as possible. D. All of the above.
Description : Under normal conditions, the speed of a two-speed squirrel cage induction motor is changed by varying the ____________. A. frequency of the applied voltage B. resistance in the rotor circuit C. number of field poles D. amplitude of the applied voltage
Description : Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency? A. A four-pole synchronous motor under normal load. B. A four-pole induction motor under ... A six-pole synchronous motor under normal load. D. A six-pole induction motor under full load.
Description : One item listed on the name plate of a cargo pump motor is 'degrees centigrade rise.' This number is based on _____________. A. normal temperature change from cold to hot B. an ambient temperature ... . minimum heat rise from no load to full load D. maximum degrees centigrade rise from absolute zero