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 : 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
Last Answer : Answer: C
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 : 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
Last Answer : Answer: D
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 : 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 : 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 : 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 : 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 : If your multimeter gives a reading in ohms when testing each end of each conductor of a three-conductor cable, this indicates ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited
Description : D.C. motor brush adjustment includes attention to _________. A. angle with the commutator and clearance within the holder B. brush length and pigtail tightness C. grade of material and surface dirt conditions D. all of the above
Description : What is the resistance value indicated on the multimeter scale illustrated, if the range switch is set at R X 100, and the needle is at the position indicated by the letter 'R'? EL-0047 A. 6.0 ohms B. 162.5 ohms C. 600 ohms D. 16,250 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 100, and the needle is at the position indicated by the letter 'Y'? EL-0047 A. 220 ohms B. 240 ohms C. 2,400 ohms D. 24,000 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'A'? EL-0047 A. 10 ohms B. 100 ohms C. 200 ohms D. 1,000 ohms
Description : You are calibrating a multimeter using internal batteries to supply power for resistance measurements. However, you are unable to adjust the pointer to 'zero' using the adjustment knob. Therefore, you should ... change scales to the R X 100 scale and adjust using the 'zero ohms' adjusting knob
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'F'? EL-0047 A. 0.6 ohms B. 6 ohms C. 9.6 ohms D. .38 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'D'? EL-0047 A. 7.8 ohms B. 8 ohms C. 3.6 ohms D. .36 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'R'? EL-0047 A. 6 ohms B. 6.8 ohms C. 1.7 ohms D. 167 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'X'? EL-0047 A. 8 ohms B. 6.2 ohms C. 1.57 ohms D. 150 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'C'? EL-0047 A. 1.3 ohms B. 4.8 ohms C. 13 ohms D. 121 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'B'? EL-0047 A. 1.45 ohms B. 7.2 ohms C. 37 ohms D. 70 ohms
Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1 and the needle is at the position indicated by the letter 'Y'? EL-0047 A. 2.2 ohms B. 24 ohms C. 240 ohms D. 2,400 ohms
Description : 2. Differential manometer measures the (A) Absolute pressure (B) Gauge pressure (C) Pressure difference (D) Pressure gradien
Last Answer : (C) Pressure difference
Description : Pressure of the order of 10" torr can be measured by (A) Bourdon tube (B) Pirani Gauge (C) Micro-manometer (D) Lonisation gauge
Last Answer : Answer: Option D
Description : Air velocity in ducts can be measured by using and manometer a) Orifice meter b) Borden gauge c) Pitot tube d) Anemometer
Last Answer : Pitot tube
Description : You are given a mercury manometer range 0 -760 mm ? A vacuum gauge reads 60 mm vacuum. The test manometer reads 50 vacuum ? Which of the two in correct.
Last Answer : The transmitter is correct because 760 - 50 = 710 mm abs.
Description : Which of the following statements represents the FIRST step in seating new brushes on slip rings? A. Wrap sandpaper around the slip rings and slide it back and forth between the brushes and the slip rings. B. ... to 4 hours. D. Apply seating compound under the brushes and run at no load for 2 hours.
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 : Coast Guard Regulations (46 CFR), require that an indicating light at the propulsion control station will operate if overloading or overheating occurs in a _______________. A. forced draft blower motor B. steering gear motor C. fuel pump motor D. condensate pump motor
Description : A four pole turbogenerator is used in conjunction with a 160 pole propulsion motor. If the generator is turning at 3,200 RPM, what is the current speed of the propeller? A. 40 RPM B. 60 RPM C. 80 RPM D. 100 RPM
Description : The prime mover of an AC two pole main propulsion generator drives the generator at 3600 RPM. If the main propulsion motor has 80 poles, what will be the propeller speed? A. 45 RPM B. 80 RPM C. 90 RPM D. 180 RPM
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 : An overload in which of the listed motors will result in the illumination of an indicating light at the propulsion control station alarm panel? A. Fuel pump motor B. Steering motor C. Condensate pump motor D. Forced draft blower motor
Description : The direction of propeller shaft rotation in a turbo-electric synchronous propulsion drive motor is changed by reversing the _____________. A. polarity of the propulsion motor B. polarity of the propulsion generator C. phase sequence of power to the motor D. phase sequence of power to the generator
Description : If you reverse both the field and the armature connections to a DC propulsion motor, _____________. A. the direction of motor rotation will change B. the brushes will become overheated C. a magnetic lock will occur in the motor D. the direction of motor rotation will remain the same
Description : The propeller shaft speed in a turbo-electric, synchronous, propulsion drive motor is changed by varying the __________. A. turbine speed B. number of motor poles C. field strength of the generator D. field strength of the motor
Description : The direction of rotation of a DC propulsion motor can be reversed by __________. A. reversing the field connections B. reversing the field and the armature connections C. wiring the field and armature in parallel D. wiring the field and armature in series
Description : When starting a DC propulsion motor the variable rheostat must FIRST be turned ____________. A. all the way to the run position then quickly back to slow B. to the slow position then gradually moved to full speed C. to the mid position D. quickly to the run position
Description : In an AC synchronous motor electric propulsion plant, propeller speed is controlled by varying the _____________. A. prime mover speed B. electric coupling field strength C. number of energized main motor poles D. propulsion generator field strength
Description : While starting a main propulsion synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. This indicates the _____________. A. motor has started ... field windings are grounded C. slip rings are dirty D. power transmission cables are grounded
Description : Which of the following statements represents an application of a silicon controlled rectifier? A. To provide DC power for a main propulsion motor. B. For use as a voltage reference diode. C. For sensing flame in an automated burner. D. To eliminate power supply hum.
Description : Which of the following statements is true concerning a polyphase synchronous propulsion motor? A. The motor is started as an induction motor. B. Resistance is gradually added to the rotor circuit. C. ... is held below the rated current. D. The field winding is energized for starting purposes only.
Description : In a diesel electric plant, raising the generator's field excitation will cause the DC propulsion motor to ________. A. increase in speed B. decrease in speed C. affect generator speed only D. affect main motor speed if done in conjunction with higher generator engine speeds
Description : On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had dropped out of synchronization with the propulsion generator? A. Excessive ... Tripped main motor interlocks C. Overheated crosstie busses D. Closed contact in the field circuits
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 of the listed instruments can be best used to locate a grounded field coil in a synchronous motor? A. Frequency meter B. Megohmmeter C. Voltmeter D. Multimeter
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 : When reading AC current with the multimeter shown in the illustration and you are unsure of the range, the range switch should be set to ___________. EL-0047 A. 10 MA/ 10 AMP with leads in the (-10 A ... leads in the (-COMMON) and (+10 A) jacks D. unable to measure AC current with this multimeter
Description : Where a thermal-acting breaker is required to be used in an area of unusually high, low, or constantly fluctuating temperatures, an ambient compensating element must be used. This element consists of ... arm B. conical spring on the contact arm C. second bimetal element D. second electromagnet
Description : The reading at 'K' on the megger scale shown in the illustration, is ______________. EL-0044 A. 400 ohms B. 4,000 ohms C. 40,000 ohms D. 400,000 ohms