Description : A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor ... the flux created by the excitation current D. the stator flux rotates in the opposite direction
Last Answer : Answer: B
Description : A multimeter can be used to measure _____________. A. resistance B. voltage C. current D. all of the above
Last Answer : Answer: D
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
Last Answer : Answer: A
Description : A multimeter may be damaged by taking a _____________. A. voltage reading while in the ammeter mode B. current reading while in the voltmeter mode C. resistance reading while in the ammeter mode D. resistance reading while in the voltmeter mode
Description : The rotor of a synchronous motor operates in synchronism with the rotating field because ______________. A. of the amortisseur windings B. the rotor is magnetically locked into step with the ... field strength varies directly with rotor slip D. the stator flux rotates in the opposite direction
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 : 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
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 : Which of the listed statements is correct when using an analog multimeter as an ohmmeter? A. The pointer should be adjusted to zero each time a new resistance range is selected. B. The ... C. Ohmmeters are not sufficiently sized to measure conductor insulation resistance. D. All of the above.
Description : An electrical connection between the wiring of an electric motor and its metal frame is known as a/an _____________. A. eddy current B. ground C. impedance D. flux leakage
Description : Electrical power is expressed in _____________. A. ohms B. volts C. amps D. watts
Description : Fuses are usually rated in _____________. A. watts B. amps only C. volts only D. amps and volts
Description : One horsepower is equal to _____________. A. 500 watts B. 663 watts C. 746 watts D. 1,000 watts
Last Answer : Answer: C
Description : Hall voltage is directly proportional to A. current B. electric field C. magnetic flux density D. all of above
Last Answer : magnetic flux density
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 : A multimeter is used to measure – (1) current (2) voltage (3) resistance (4) All of the above
Last Answer : (4) All of the above Explanation: A multimeter or a multitester, also known as a VOM (Volt-Ohm meter), is an electronic measuring instrument that combines several measurement functions in ... or digital circuits-analog multimeters (AMM) and digital multimeters (often abbreviated DMM or DVOM.)
Description : A multimeter is used to measure (1) current (2) voltage (3) resistance (4) All of the above
Last Answer : All of the above
Description : The Tesla and the Gauss are units of measure of: w) conductance x) magnetic field strength y) magnetic flux z) electrical current
Last Answer : ANSWER: X -- MAGNETIC FIELD STRENGTH
Description : A device which can be used to check the calibration of a circuit breaker is a _________________. A. 500 volt megohmmeter B. portable low voltage high current testing unit C. standard digital multimeter D. clamp-on voltmeter
Description : When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only ... being tested D. so as not to load down the circuit and obtain erroneous voltage readings
Description : Reversing the current flow through a coil will ___________. A. reduce the amount of flux produced B. have no effect on the eddy currents produced C. reduce the power consumed D. reverse its two-pole field
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 : Materials that retain a large part of their magnetization, after the magnetizing force is removed, are said to have _____________. A. low hysteresis loss B. high flux density C. high permanence D. high permeability
Description : The speed of a multi-speed, squirrel-cage, induction motor operating in a fixed frequency system can be changed by _____________. A. reconnecting stator windings for different numbers of poles B. ... sequence of the applied voltage D. reconnecting the stator so that no poles have the same polarity
Description : Transformer cores are laminated to reduce _____________. A. eddy currents B. secondary flux C. leakage flux D. all of the above
Description : A shading coil used in an AC magnetic controller, functions to _____________. A. reduce vibration and noise in the contactor B. prevent flux buildup in the operating coil C. eliminate arcing when the contacts close D. energize the operating coil and 'pull in' the contacts
Description : A megohmmeter is used to measure _____________. A. voltage B. dielectric strength C. current D. power
Description : Which one of the following statement is correct? (A) Radiant energy expressed in Joules, is the energy associated with electromagnetic radiation (B) The rate of transfer of radiant energy is called flux ... ) The radiant energy which falls upon a surface is termed as irradiance (D) All of these
Last Answer : Answer: Option D
Description : The magnetic flux density is directly proportional to the magnetic field intensity. State True/False. a) True b) False
Last Answer : a) True
Description : Electronic equipment used to measure standing wave ration. A. Reflectometer B. Wavemeter C. Altimeter D. Multimeter
Last Answer : A. Reflectometer
Description : Which tester is used to measure SWR? A. Spectrum analyzer B. Multimeter C. Reflectometer D. Oscilloscope
Last Answer : C. Reflectometer
Description : Pick up the correct statement from the following: (A) Permeability is a measure of conducting the magnetic lines of force in the material (B) Permeability is a measure of the extent to which magnetic ... magnetic flux density (B) to the field strength of the magnetizing field (D) All of these
Description : An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from ... C. any suitable ground to any available line lead D. any field pole to each field coil lead
Description : If an AC generator experiences voltage failure, the cause may be _____________. A. an open in the field circuit B. the brushes shifting out of the neutral plane C. excessive locked-rotor current D. a rotating slip ring
Description : An equalizing connection between two compound-wound DC generators when paralleled, serves to _____________. A. reverse the polarity of the incoming generator as the series field weakens B. automatically ... the series field of the incoming generator D. parallel the series fields of the generators
Description : If field excitation is suddenly lost to an alternator operating in parallel, that alternator will _____________. A. supply excessive current to the bus B. operate at the same load, but with reduced voltage C. lose its load and tend to overspeed D. become overloaded and slow down
Description : In an alternating current electrical system, a low system power factor is a direct sign of _____________. A. wasted energy B. efficient operation C. a short in the exciter field windings D. an excessive number of minor system grounds
Description : A DC generator is used to supply direct current in order to maintain an AC generator field and is known as a/an _____________. A. rotor B. stator C. exciter D. armature
Description : The direction of rotation of the winch shown in the illustration is changed by reversing the _____________. EL-0102 A. direction of current through the shunt field B. polarity of voltage at 'S1' and 'S2' C. direction of current through the armature D. polarity of voltage at 'L1' and 'L2'
Description : In a compound-wound motor, a portion of the line current flows through the _____________. A. inertial poles B. stator C. shunt field coils D. frame
Description : In a series wound motor, the current passing through the field windings is also passing through the _____________. A. armature B. shunt field C. reactance comparator D. laminations
Description : In a three-phase, squirrel-cage type, induction motor the rotating magnetic field is established by the _____________. A. current induced in the rotor windings B. application of a three-phase voltage ... caused by the induced current in the squirrel-cage bars with the magnetic field of the stator
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 : The simplest method of controlling the terminal voltage of compound-wound DC generator is with a _____________. A. hand-operated field rheostat connected in series with the shunt field circuit B. ... in series with the load D. balance coil diverting neutral current through the shunt field
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 : What power is consumed by a heating element using a current of 20 amperes at 120 volts? A. 20 watts B. 66.67 watts C. 720 watts D. 2400 watts
Description : What is the wattage of a heating element drawing a current of 30 amperes, at 120 volts? A. 30 watts B. 99.97 watts C. 360 watts D. 3600 watts
Description : The eddy current loss in an a-c electric motor is 100 watts at 50 Hz. Its loss at 100 Hz will be (A) 25 watts (B) 59 watts (C) 100 watts (D) 400 watts
Last Answer : (D) 400 watts
Description : A shore power circuit breaker should be closed only _____________. A. when the ship's generators have been directly paralleled to those on shore B. in a shipyard C. if a quick disconnect coupling is used D. when the ship's generators have been removed from the bus
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