Modern handheld digital tachometers operate by counting light pulses returned to the unit by ______________. A. the tach generator B. either the coupling or shaft C. a small bulb attached to the shaft D. a piece of reflective tape

1 Answer

Answer :

Answer: D

Related questions

Description : A handheld digital tachometer could give a bad reading if ___________________. A. aimed directly at the shaft B. partially aimed at a 60 Hz. fluorescent light C. positioned 5-10 inches from the shaft D. the tape is too shiny

Last Answer : Answer: B

Description : Which of the following is also known as reflective scanner? A. Handheld scanner B. Flatbed scanner C. Drum scanner D. None of the Above

Last Answer : B. Flatbed scanner

Description : As shown in the illustration, the function of the switch labeled 'PFSW' is to determine the ______________. EL-0003 A. bus frequency B. reactive volt amperes of the bus C. frequency of either generator D. power factor of either generator

Last Answer : Answer: D

Description : If the bearings of an electrical generator are failing more frequently than expected and the lubricating oil is sludging then you should ______________. A. check the connections to the output leads B. ... replace the bearing with a sealed roller type D. replace the thrust bearing of the prime mover

Last Answer : Answer: B

Description : The horizontal line which cuts across 'L1' shown in figure 'A' of the illustration indicates a/an ______________. EL-0091 A. iron core B. saturable core C. air gap D. capacitive coupling

Last Answer : Answer: B

Description : Which method of digital data encoding does NOT return the tape to neutral between pulses but, instead, saturates the tape positively or negatively as the incoming data changes between zero and one?

Last Answer : Non-return-to-zero (NRZ) encoding.

Description : Which digital data encoding method records a digital one as a positive pulse and a digital (zero) as a negative pulse and returns the tape to neutral between pulses?

Last Answer : Return-to-zero (RZ) encoding.

Description : What format of digital tape recording takes a serial input stream of data pulses, breaks them up, and records them on more than one data track?

Last Answer : Serial-parallel digital magnetic tape recording.

Description : In digital magnetic tape recording, the series of recorded digital pulses can represent what three types of data?

Last Answer : a. Data used by digital computers. b. Pulsed squarewave signals. c. Digitized analog waveforms.

Description : To protect the rotor of a motor disassembled for maintenance or overhaul, it should be ___________________. A. suspended by wire slings in one corner of the shop B. stowed upright on its shaft C. supported by two 'V' notched wood blocks D. returned to the frame as soon as the bearings are removed

Last Answer : Answer: C

Description : Electric propulsion coupling excitation is reduced at slow speeds to ___________. A. increase speed control B. increase shaft torque C. prevent coupling overheating D. prevent coupling slippage

Last Answer : Answer: C

Description : Where are those reflective hand tapes sold? To make a pedestrian visible at night? Thank you

Last Answer : Drugstores, stationery, newsagents and similar stores. It's everywhere.

Description : What is the best reflective tape?

Last Answer : Your best bet for reflective tape comes from the people who make the most tape in the world: 3M. Bicyclists swear by their Scotchlite Reflective Tape. This can be found at any good bicycle store ... for light colors like silver or white, and avoid darker colors like red for best reflective quality.

Description : If the driving torque, such as that produced by a diesel engine, creates pulsations when coupled with a synchronous generator operating in parallel; the generator rotor may be periodically pulled ahead or behind ... as it rotates. This co A. hunting B. direct coupling C. peaking D. harmonic coupling

Last Answer : Answer: A

Description : If the driving torque, such as that produced by a diesel engine, creates pulsations when coupled with a synchronous generator operating in parallel; the generator rotor may be periodically pulled ... windings B. direct coupling C. increase governor speed droop D. decreasing governor speed droop

Last Answer : Answer: A

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

Last Answer : Answer: A

Description : The source of emergency lighting and power at loss of normal ship's power on a cargo vessel should be obtained from the ______________. A. emergency generator supply to the emergency ... switchboard C. battery supply to the main switchboard D. turbogenerator supply to the emergency switchboard

Last Answer : Answer: A

Description : As shown in the illustration, the motor generator(M-G) set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Last Answer : Answer: C

Description : When paralleling two alternators using three synchronizing lamps, the flickering of all three lamps becomes progressively slower and slower. This means the ______________. A. frequency of the incoming ... the bus D. terminal voltage of the incoming alternator is approaching that of the bus

Last Answer : Answer: A

Description : The purpose of the reverse power relay, provided on a ship's service alternator panel, is to trip the circuit in the event of ______________. A. main circuit overload B. high power transfer C. generator overspeeding D. alternator motorization

Last Answer : Answer: D

Description : As shown in the illustration, operating the reversing switch will change the polarity of the ______________. EL-0101 A. generator field B. generator armature C. motor armature D. all of the above

Last Answer : Answer: D

Description : As shown in the illustration, the M-G set's three-phase motor drives the ______________. EL-0101 A. motor and the generator B. motor and the exciter C. generator and the exciter D. main field and the interpole field

Last Answer : Answer: C

Description : The output voltage of a 440 volt, 60 Hz AC generator is controlled by the ______________. A. load on the alternator B. load on the prime mover C. speed of the prime mover D. exciter output voltage

Last Answer : Answer: D

Description : Why does the auto industry think that tachometers are necessary in passenger cars?

Last Answer : So you know when to shift up?

Description : Where can I go to find a comparison table of portable tachometers?

Last Answer : www.checkline.com provides the opportunity of comparision of portable tachometers. they offer a complete line of Tachometer, Contact Tachometer and Combination Digital Hand-Held Tachometer.

Description : Is the filament resistance lower or higher in a 500 watt light bulb than in a 100 watt light? Assume that both bulbs have been designed to operate at 110 volts. 

Last Answer : ANSWER: LOWER

Description : A 100-watt light bulb is left on for 10 hours. Electricity is 10 cents per kilowatt-hour. How much did it cost to operate the light bulb?

Last Answer : ANSWER: 10 CENTS

Description : Why is it desirable to operate paralleled AC generators at the same power factor? A. Circulating currents are kept to a minimum. B. Field excitation losses are kept to a minimum. C. Generator ... will have a lesser tendency to hunt. D. Because a power factor increase will decrease kilowatt output.

Last Answer : Answer: A

Description : On electrical generators one of the bearings is isolated from the bedplate. This insulating block should not be painted and must be kept clean to ___________. A. protect operating personnel from shock ... the prime mover as it warms up D. eliminate shaft currents to prevent damaging the bearings

Last Answer : Answer: D

Description : The reactive power drawn by a motor from an AC generator is the power which is _____________. A. used to establish the magnetic field of the motor B. lost in overcoming friction in the ... by current flow through the windings D. transmitted directly through the rotor shaft to perform useful work

Last Answer : Answer: A

Description : One of the generator bearing shells is generally insulated from the end housing in order to prevent _____________. A. rapid brush wear B. residual magnetism leak off C. excessive field winding heat D. circulation of shaft currents

Last Answer : Answer: D

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

Last Answer : Answer: D

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

Last Answer : Answer: C

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

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Description : The conversion of the throttle command voltage to the signal necessary to achieve the desired shaft RPM is accomplished by the _____________. A. ahead or astern function generator of the ... circuit C. operational amplifiers in the autorotation circuit D. long time constant amplifier circuit

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Description : A watchmaker was telephoned urgently to make a house call to replace the broken hands on a clock. He was sik so he sent his apprentice.The apprentice was thorough. When he finished inspecting the clock ... had to agree.Early the nect morning, the client telephoned to say the clock has ap -Riddles

Last Answer : As the problem says the apprentice mixed up the hands so that the minute hand was short and the hour hand was long. The first time the apprentice returned to the client was about 2 hours and 10 ... hand made 13 full circles and 5 minutes, reaching 7, So the clock showed the correct time again.

Description : Acknowledgement card attached to an unclaimed/returned registered article for redelivery to sender should be a) Delivered back to sender along with article b) Filled along with delivery slips c) Destroyed d) None of these

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Description : In the event of an error in a mail list and when a revised or corrected mail list is received a) The revised document can be kept safely in the correspondence file b) The revised document can be ... each other a note being added on the original d) The error mail list should be returned to sender

Last Answer : c) Both the list s should be retained on record attached to each other a note being added on the original

Description : A locomotive of weight 100 tonnes is attached to train of wagons weighing 1000 tonnes. The locomotive pulls the wagons with a constant velocity of 36 km/hour. When the coupling between the train and wagons breaks, the wagons roll on 95 m in ... would be a.0.36 m b.0.44 m c.0.77 m. d.0.5 m e.0.66 m

Last Answer : d. 0.5 m

Description : If shaft diameter is 60mm, how many bolts are recommended for rigid flange coupling? a) 2 b) 3 c) 4 d) 5

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Description : If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the diameter of each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. Permissible tensile stress is 80N/mm2. a) 27mm b) 25mm c) 23mm d) 21mm

Last Answer : a) 27mm

Description : If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the tensile force on each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. a) 51234.4N b) 45968.3N c) 41666.7N d) None of the listed

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Description : If shaft diameter is 40mm, calculate the length of sleeves in clamp coupling. a) 80mm b) 140mm c) 100mm d) 120mm

Last Answer : b) 140mm