In a three-phase, open-delta connected transformer, the line current is equal to _____________. A. the phase current B. three times the phase current C. the sum of any two phase currents D. the difference of any two phase currents

In a three-phase, open-delta connected transformer, the line current is equal to _____________. A. the phase current B. three times the phase current C. the sum of any two phase currents D. the difference of any two phase currents
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Answer: A  
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Description : In the illustrated three phase alternator, line voltage is _________. EL-0074 A. 1.73 times the phase voltage B. equal to the phase voltage C. phase voltage divided by 1.73 D. unable to answer this question without knowing the line current

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A three-phase, squirrel cage, induction motor will run hot due to _____________. A. open stator coils B. high power factor C. dirty or corroded slip rings D. reversed commutating poles

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What is the maximum allowable primary current of a 2 KVA step-down transformer with a four to one turns ratio if connected across a 440 volt line? A. 1.1 amps B. 4.5 amps C. 18.1 amps D. 27.7 amps

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Description : What is the difference between delta-delta, delta-star transformer?

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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

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

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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

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On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________. A. insulation resistance B. eddy currents C. capacitance D. armature reactance

Description : On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________. A. insulation resistance B. eddy currents C. capacitance D. armature reactance

Last Answer : Answer: A

In an induction motor, rotor currents are circulated in the rotor by _____________. A. slip rings and brushes B. an armature and brushes C. inductive reaction of the rotating stator field D. external variable resistors

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Description : Explain Three Phase Bidirectional Delta Connected Controller.

Last Answer : Three Phase Bidirectional Delta Connected Controller:

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Last Answer : Answer: A

The rotation of a three-phase induction motor can be reversed by _____________. A. interchanging any two of the three line leads to the stator B. disconnecting one of the three line leads to the stator C. switching the shunt field coil leads D. permanently disconnecting any two of the three line leads to the stator

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Last Answer : Answer: A

To check the three line fuses of a three-phase system consisting of a three-phase motor, you must _____________. A. place the starter in the 'stop' position B. make sure the motor is operating at full load to guard against a false reading C. place the leads across the 'hot' ends of the fuses D. place the leads across the bottom ends of the fuses

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Last Answer : Answer: A

Most three-phase induction motors of five horsepower or less, are started by _____________. A. autotransformer starters B. resistor starters C. across-the-line starters D. reactor starters

Description : Most three-phase induction motors of five horsepower or less, are started by _____________. A. autotransformer starters B. resistor starters C. across-the-line starters D. reactor starters

Last Answer : Answer: C

Most three-phase induction motors used for driving engine room auxiliaries are started by _____________. A. resistor starters B. across-the-line starters C. impedance starters D. reactor starters

Description : Most three-phase induction motors used for driving engine room auxiliaries are started by _____________. A. resistor starters B. across-the-line starters C. impedance starters D. reactor starters

Last Answer : Answer: B

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 supply to the stator windings C. laminated steel core and aluminum conductors in the rotor D. interaction of the magnetic field caused by the induced current in the squirrel-cage bars with the magnetic field of the stator

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

Last Answer : Answer: B

The speed of a three-phase squirrel-cage induction-type motor operating in a fixed frequency system is varied by changing the _____________. A. number of phases to the motor B. number of stator poles C. locked rotor current D. resistance of the rotor winding

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Last Answer : Answer: B