Description : The item referred to as a pigtail on a DC motor brush rigging is a/an ______________. A. feather spring B. uninsulated wire C. flexible spring adjuster D. brush holder
Last Answer : Answer: B
Description : In general, D.C. propulsion motor brush sparking can be caused by _______________. A. incorrect brush grade, pressure or position B. a concentric commutator C. a dark chocolate colored commutator D. all of the above
Last Answer : Answer: A
Description : Chattering of the collector ring brushes on a generator may be remedied by _____________. A. lubricating brush holders B. reinsulating the brushes C. cleaning the collector rings D. increasing length of pigtail
Last Answer : Answer: C
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 : If a D.C. motor hums, but does not run when energized, which of the listed conditions could exist? A. Incorrect lead connections B. Incorrect brush setting C. A dirty commutator D. All of the above are correct.
Last Answer : Answer: D
Description : Due to which of the following factors the brush wear rate is altered ? (a) Speed of the machine (b) Contact pressure (c) Surface conditions of brush and commutator (d) Excessive sparking (e) All of the above
Last Answer : Ans: E
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 : An important factor in reducing D.C. motor commutator wear is _______________. A. keeping the ambient humidity as low as possible B. ensuring a very low brush current density C. establishing the copper oxide surface film D. all of the above
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 : 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 : The direction of rotation of a DC propulsion motor can be changed by reversing the _____________. A. brush holder position B. polarity of the field poles C. brush staggered order D. motor interpole connections
Description : In addition to undercutting the mica, proper maintenance of a D.C. motor's commutator includes _______________. A. side-cutting the copper segments and insulating the slots B. coating the copper surface with light machine ... in an oven at a maximum of 95°C for not over 8 hours D. all of the above
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 : D.C. propulsion motor brush pressure depends on the brush grade used and in practice is set with a ______________. A. multimeter B. manometer C. spring scale D. compound gauge
Description : The function of a brush and commutator arrangement in a dc motor is to (1) produce unidirectional torque (2) produce unidirectional current in the armature (3) help in changing the direction of rotation of the armature (4) reduce sparking
Last Answer : The function of a brush and commutator arrangement in a dc motor is to produce unidirectional torque
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 : Which of the following precautions should you take when securing propulsion generators and motors for an extended period of time? A. Disconnect the brush pigtails from their contacts and circulate air ... Lift the brushes from commutator collector rings and circulate cool dry air through the units.
Description : Basic electrical motor action depends on _______________. A. a conductor rotated within a magnetic field B. a current carrying conductor placed in a magnetic field C. the relative force of the commutator and commutating poles D. the relative force of the armature and interpoles
Description : A commutator's protective oxide film can be destroyed by _________________. A. periods of low humidity B. very low brush current density C. improper brush grade D. all of the above
Description : Which of the listed conditions might contribute to very rapid wearing of a DC machine's commutator bars? A. A grounded commutator bar B. Using improper carbon brushes C. Aligning the front and rear mica V-rings improperly D. An open circuit in the armature
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 : 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 : Which of the listed colors properly describes a DC motor commutator when correct commutation is taking place? A. Shiny blue B. Burnished green C. Brick red D. Chocolate brown
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
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
Description : The most effective method of locating a loose commutator bar in a D.C. motor is by _____________. A. visual inspection B. jiggling each by hand C. sounding each bar with a light weight hammer D. checking with a calibrated torque wrench
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 : The function of the commutator in a DC motor is to ________. A. reverse the flow of current through the armature B. reverse the flow of current in the field poles C. reduce the reluctance of the magnetic path through the motor D. shift the neutral running plane of the brushes to prevent sparking
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.
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 : 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 : Much of the disciplinary and motivational difficulties experiences by teachers stem from Options: A) Personal mal adjustment on the part of teachers or pupils B) The failure of the curriculum ... education D) The relatively greater appeal of other interests competing for the child's attention
Last Answer : B) The failure of the curriculum to meet pupil's needs
Description : Sparking at the brushes of a DC propulsion motor can be the result of ____________. A. improper brush pressure B. improper brush seating C. reversed interpole polarity D. all of the above
Description : A three-phase, squirrel cage, induction motor will run hot due to a/an ______________. A. improper brush position B. reversed commutating pole C. shorted stator D. high power factor
Description : One of the generator or motor bearings is generally insulated from the end housing in order to prevent ________. A. rapid brush wear B. current leakage from the shaft C. excessive field winding heat D. circulation of shaft currents induced in the machine's frame
Description : Propulsion DC motor brush pressures can be calculated by _____________. A. dividing the brush contact area by the spring pressure B. subtracting the brush contact area from the spring pressure C. ... force by the brush contact area D. subtracting the spring pressure from the brush contact area
Description : Insufficient brush pressure on a DC motor may cause _______. A. generator overload B. excess residual magnetism C. water vapor absorption D. sparking of the brushes
Description : On some diesel-electric ships, the DC propulsion motor will only attain half speed when the generator fields are fully excited. Speeds above this are obtained by _____________. A. rotating brush ... B. raising the generator engine speed C. lowering the generator engine speed D. decreasing excitation
Description : The purpose of a short circuit forcing module (short time trip) installed in a branch line is to provide ____________. A. high speed clearance of low impedance short circuits in the branch B. ... C. isolation of short circuits by selective tripping of branch circuit breakers D. all of the above
Description : In the illustrated motor, roller bearings are used because __________. EL-0001 A. of their ability to absorb moderate thrust loads B. they electrically insulate the rotor from the frame reducing ... clearance between the rotor and stator is generally as close as mechanical tolerance will permit
Description : The shafts will have same strength on the basis of torsional rigidity, if (A) Diameter and length of both shafts is same (B) Material of both shafts is same (C) Angle of twist for both shafts is same (D) All of above conditions are satisfied
Last Answer : (D) All of above conditions are satisfied
Description : The shafts will have same strength on the basis of torsional rigidity, if (a) diameter and length of both shafts is same (b) material of both shafts is same (c) angle of twist for both shafts is same (d) all of above conditions are satisfied
Last Answer : (d) all of above conditions are satisfied
Description : The term “DISREGARD” means: a. Ignore b. Cancel the last clearance c. You have not been cleared d. Pay no attention to what I say
Last Answer : a. Ignore
Description : For safe landing and takeoff, the following factors need to be carefully considered : 1. Cross-wind 2. Runway grade 3. Runway width and side clearance 4. Obstructions (a) 1, 2 and 3 only (b) 1, 2, 3 and 4 (c) 1, 3 and 4 only (d) 2, 3 and 4 only
Last Answer : (b) 1, 2, 3 and 4
Description : Seating the brushes on a D.C. motor is first accomplished using ________________. A. a file for cutting the approximate curvature followed by sandpaper for the final fit B. sandpaper with the motor not ... for the finishing cut D. course lapping compound, followed by a medium and then a fine grade
Description : Which cough syrup works best for when the throat is also itchy and there is chest tightness?
Last Answer : I am a big fan of Mucinex for such things. The main ingredient thins and loosens muchus, helping with chest tightness and preventing it from becoming something like bronchitis. I take the tablets, but ... Tylenol for fever and pain plus some Fisherman's Friends cough drops and a good cup of tea.
Description : tightness of the sciatic nerve can result in lower back pain. -General Knowledge
Last Answer : The given statement is true.
Description : My anxiety , chest tightness , body tingling. Can I eat Endever 10 ?
Last Answer : : You can take INDEVER 10 for the symptoms of your high blood pressure . However, take the medicine according to the advice of a good doctor.
Description : What can cause leg stiffness or tightness?
Last Answer : Lots of information here http://www.livestrong.com/article/136909-causes-leg-pain-stiffness/ Please consult a doctor if the stiffness continues.