Description : A short in the shunt field of a DC motor is best located by _____________. A. visual inspection of the commutator B. applying AC voltage to each field coil and measuring the voltage drop across ... using a growler and hacksaw blade D. isolating each coil from the others and using a megohmmeter
Last Answer : Answer: B
Description : An open in the armature of a DC motor is suspected, but is not found by visual inspection of the commutator. The next step in troubleshooting this problem is to ________________. A. conduct a ... windings C. conduct an insulation resistance test of the armature D. test the commutator for a ground
Last Answer : Answer: A
Description : If only one brush on a commutator is sparking excessively, you should look for _____________. A. a high commutator bar B. copper imbedded in the brush C. a loose commutator bar D. flux in the commutating zone
Description : When using a multimeter for resistance measurements, it should be calibrated by clipping the loose ends of the leads together and _____________. A. setting the instrument pointer at 'zero' ohms B. ... the plus and minus terminals D. using a special purpose resistance measuring instrument (a bridge)
Description : The most practical method used for resurfacing a ship's service motor commutator is to _____________. A. turn it down in the ship's lathe B. use a grinding rig C. use a hand stone D. burnish it with commutator stones
Description : When removing ball or roller bearings from the shaft of a motor, you should use a _____________. A. rawhide hammer B. brass mallet C. wheel puller D. soft iron pry bar
Last Answer : Answer: C
Description : Excessive heat in an operating motor controller can result from _____________. A. a closed starter contact B. loose connections C. missing arc chutes D. low motor starting torque
Description : Temporary repairs to an open DC propulsion armature coil can be made by _____________. A. connecting the coil ends directly to a pair of negative brushes B. disconnecting coil ends, insulating ... C. grounding the coil ends and short circuiting the commutator bar D. removing the sparking brushes
Description : Routine A.C. motor maintenance should include periodic ______________. A. thermometer readings at normal loads to detect abnormal temperature rises B. inspection of the motor's internals for loose rotor bars ... C. bearing replacement each year using sealed units if available D. all of the above
Description : Uneven wear of the commutator surface on a direct current propulsion motor can be caused by _____________. A. rapid change in load B. excessive operation at light load C. incorrect brush staggering D. unequal pole spacing
Description : A useful instrument for checking A.C. motor performance by measuring possible unbalanced currents is the _____________. A. hand or battery-operated megger B. vibrating-reed frequency meter C. hook-on voltmeter-ammeter D. D'Arsonval iron-vane probe
Description : In an AC generator, direct current from a separate source is passed through the windings of the rotor _____________. A. by means of slip rings and brushes B. by means of a commutator C. by means of rotating bar magnet D. to minimize the danger of arc over
Description : Complete controller maintenance includes _____________. A. periodic testing of protective devices B. checking for loose or worn contacts and weak springs C. maintaining a sufficient supply of spare parts D. all of the above
Last Answer : Answer: D
Description : The torque produced by a DC motor armature is the product of the force acting at the armature surface multiplied by _____________. A. work done by the armature in one revolution B. effective ... arm at the center of rotation of the armature D. perpendicular distance to its center of rotation
Description : Periodic testing by a shoreside support technician using a special camera which can detect potentially dangerous loose or corroded bus bar and controller connections is termed ______________. A. heat sensitive thermography B. visual pyrotronics C. corrosion electrolysis D. electric vibroanalysis
Description : Aboard ship, a grounded field coil in an AC motor can be determined by using a _________________. A. portable growler B. galvanometer C. visual inspection D. megohmmeter
Description : Sparking at the brushes of a running motor could be an indication of _____________. A. normal operation B. a dirty commutator C. increased brush capacity D. water vapor absorption
Description : A flickering ground detection lamp on a DC system would indicate a _____________. A. multiple-ground condition in the distribution system B. ground in an armature coil of an operating machine C. ground in a motor accompanied with a short D. short between two adjacent bars of the generator commutator
Description : In D.C. motor construction, the armature coils' ends are _______________. A. soldered to the commutator bar risers B. imbedded into core slots C. crimped together with brush pigtails D. spliced with the field windings
Description : If a three-phase induction motor is operated under a light load and it develops an open in one of its supply lines, the motor will _____________. A. continue to run, but will vibrate and have reduced ... speed up due to the reduced number of poles C. run cooler due to reduced current flow D. stop
Description : The ground indicating light on the main electrical switchboard is indicating a ground. The best procedure for locating the grounded circuit is to _____________. A. trace the circuit paths while looking for ... a time, until the lights no longer indicate a ground D. check all circuits for continuity
Description : Optical cable testers are used for ∙ a. Checking refractive index ∙ b. Light power out of a fiber ∙ c. Non-calibrated light into a fiber
Last Answer : b. Light power out of a fiber
Last Answer : ∙ b. Light power out of a fiber
Description : The purpose of the commutator and brushes on a DC generator is to _____________. A. transfer generated direct current voltage from the armature to the line B. convert the alternating voltage ... contact method to excite the field D. reduce sparking between the armature and the carbon brushes
Description : Encrusted dirt accumulated inside a motor should be removed with a _____________. A. fiber scraper B. pointed welding rod C. hammer and chisel D. paint scraper
Description : Multiple grounds have developed and were initialy indicated by the grounddetecting system as one ground. The FIRST step in locating the grounds is to _____________. A. examine the main bus bars ... no longer indicates any grounds C. change over generators D. check each circuit with a megohmmeter
Description : A ground is indicated by the ground-detecting system on the main electrical switchboard. The FIRST step in locating the actual ground is to _____________. A. close all circuit breakers in ... ground detection system indicates normal C. change over generators D. check each circuit with a megohmmeter
Description : Gathering information about customers or market is known as _____________ 1. Customer inspection 2. Checking market area 3. Need of a bank 4. Market Research 5. None of these
Last Answer : Market Research
Description : A capacitor discolored due to excessive heat should be _____________. A. calibrated using a capactance wheatstone bridge B. replaced and the reason for the overheating found C. cooled with a spray ... purpose D. resoldered with care taken to insure that the origional cold solder joint is repaired
Description : A capacitor discolored due to excessive heat should be _____________. A. calibrated B. replaced C. cooled D. soldered
Description : In flange splices when the number of hammer and hand loose rivets is 30% or more of the total rivets on any side of the splice location, a) Need no be renewed b) wait for 100% loose rivets c) all the rivets should be renewed.* d) None of the above
Last Answer : c) all the rivets should be renewed.*
Description : Renewal of slack rivets should be taken up in steel girder bridges: a) All rivets which are hand loose or which have lost 50% of their head by corrosion. b) All hammer loose rivets where corrosion has set ... . c) In end stiffeners when the percentage of hammer loose rivets is >30% d) All the above*
Last Answer : d) All the above*
Description : Which of the following is a characteristic of fractional horsepower repulsion start motors? A. They start with a rotating stator field. B. The short circuiting ring is removed from the commutator while ... brushes are removed from the commutator while starting. D. They have a low starting torque.
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 : .For an onlay preparation, which of the following is the MOST EFFECTIVE means for verifying adequate occlusal clearance A. Wax bite chew in B. Proper depth cuts C. Visual inspection D. Articulating paper
Last Answer : A. Wax bite chew in
Description : What is a hydraulic torque wrench used for?
Last Answer : A hydraulic torque wrench is a tool used to exert torque on a fastener, to either loosen or fasten to satisfaction. Torque is the twisting force used by the body and the tool to achieve your results. ... at supply chains (Lowes, Home Depot†) or rent, depending on how often you plan to use it.
Description : An increase in the amount of current flow through the armature of a shunt motor is the final result of a/an _____________. A. increase in the load on the motor B. decrease in the load on the motor C. increase in counter EMF D. decrease in armature torque
Description : The twisting force developed by a motor and applied to a shaft is called _____________. A. magnetism B. electromotive force C. torque D. voltage
Description : If the centrifugal switch or relay used for cutting out the starting winding of a split-phase induction motor fails to open once the motor is in operation, the _____________. A. motor will overspeed B ... C. motor will immediately stall under load D. motor torque will be above normal at rated speed
Description : A characteristic of a wound-rotor induction motor, with a high resistance rotor winding, is _____________. A. low starting torque B. high starting torque C. high speed D. low starting voltage
Description : If an induction motor were to be operated at 90% rated voltage, _____________. A. there would be an increase in starting torque B. starting current would increase slightly C. synchronous speed would decrease slightly D. the slip would increase
Description : Regarding an induction motor, the power developed by the rotor automatically adjusts itself to the _____________. A. power required to drive the load B. speed required to drive the load C. current flow in the motor stator D. torque developed by the rotating field
Description : Reduced voltage applied to a motor during the starting period will _____________. A. result in decreased acceleration time only B. lower the starting current and increase accelerating time C. cause a greater starting torque D. increase the starting current and pump capacity
Description : The function of amortisseur, or damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency
Description : The function of damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency
Description : The purpose of a cage rotor winding placed on the rotor of a synchronous motor is to _____________. A. provide excitation to the DC field B. start the machine as an induction motor C. contribute extra torque at synchronous speed D. prevent the machine from falling out of step
Description : The torque produced by a motor when its shaft will not turn, even though rated voltage is applied to the stator, is known as _____________. A. locked-rotor torque B. pullout torque C. breakdown torque D. torque margin
Description : Autotransformer starters or compensators are sometimes used with polyphase induction motors to _____________. A. reduce the voltage applied to the motor during the starting period B. increase the voltage for ' ... to be either stepped up or down, depending on the application, to ensure full torque
Description : In the illustrated test, if the lamp fails to light on any of the three windings then _________. EL-0027 A. all three windings are grounded and the motor should be sent out for repair B. ... the motor controller and the controller should be checked D. the test should be redone at a higher voltage
Description : 65. While the nurse was checking the BP of the client, the wife was intently observing the nurse. The wife asks the nurse how to ensure accurate measurement of BP reading. Identify all the ... The client should rest quietly for 5 minutes before reading and can talk while BP is being checked
Last Answer : A. 1, 2, 3, and 4