FREE AND STUDY GAMES ABOUT TRANSFORMERS CH 7

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FREE AND STUDY GAMES ABOUT TRANSFORMERS CH 7

EXAM QUESTIONS

Qs and Ans Expert- Explanation

This Exam contains:

-Guarantee passing score -23 Questions and Answers -format set of multiple-choice -Expert- Explanation Question 1: 20. In a 3-phase circuit, power varies during a cycle but never falls to zero. T/F

Answer:

True Question 2: 8. In an electric generating power plant, all generators must be connected in __ (Chain; Line; Parallel; Series)

Answer:

Parallel Question 3: 21. Transformers are usually used to step up voltage at the point of use. T/F

Answer:

False

Question 4: 17. Magnetic force is used to rotate the coils in a generator. T/F

Answer:

False; prime mover

Question 5: 15. __is a method of synchronizing generators. (Chaining; Lights-out; Marking; Phase-timing)

Answer:

Lights-out Question 6: 13. A __ is a machine that converts mechanical energy into electrical energy by means of electromagnetic induction( Electrical transmitter; Generator; Motor drive; Transformer)

Answer:

Generator Question 7: 1. In North America, power is gene at a frequency of __. (25 Hz; 50Hz; 60 Hz; 120 Hz)

Answer:

60 Hz Question 8: 2. A __ is a device that indicates whether two AC sources to be connected in parallel are in the correct phase relationship(Alternator; Potentiometer; Rotor; Synchroscope)

Answer:

Synchroscope Question 9: 3. The __ is the voltage measured line-to-line ( Line current; Line voltage; Winding current; Winding Voltage)

Answer:

Line voltage Question 10: 6. A landfill generator runs on the methane gas created by decomposing trash. T/F

Answer:

True Question 11: 12. Describe the occurrences that resulted in the August 13th, 2003 East Coast power blackout.

Answer:

An overhead transmission line became overheated and sagged, shorting to ground when it came into contact with a tree.

Question 12: 9. The __ is the voltage measured across the windings (Line current; Line voltage; Winding current; Winding voltage)

Answer:

Winding voltage Question 13: 10. A __ produces energy when a rotting coil cuts through magnetic flux ( Generator; Motor drive; Synchroscope; Transformer)

Answer:

Generator Question 14: 11. The __ is the current flow through the lines to a load ( Line current; Line voltage; Phase current; Phase voltage)

Answer:

Line current Question 15: 7. The power in a single-phase circuit drops to zero __ every cycle. (Once; Twice; Three times; Four times)

Answer:

Twice Question 16: 22. If the line voltage is 480 V as shown in the illustration, the winding voltage is ___ V. page 99 workbook (120; 208; 240; 277)

Answer:

277 Question 17: 4. The most efficient way to send electric power over transmission lines is at the lowest current possible. T/F

Answer:

True Question 18: 23. How much power in kVA is delivered to a three-phase transformer when the line voltage applied is 480 volts and the line current is 12 amps

Answer:

9.96 Kva

Question 19: 5. The __ is the current flow through the individual windings. (Line current; Line voltage; Winding current; Winding voltage)

Answer:

Winding Current Question 20: 19. In the one-light-out method, phases are connected A to B, B to A, and C to

C. T/F

Answer:

True Question 21: 18. In the three-lights-out method, a lamp is connected as a load across each phase of the two sources, A to A, B to B, and C to

C. T/F

Answer:

True Question 22: 16. Utilities normally generate __ (Single-phase AC power; Single-phase DC power; 3-phase AC power; 3-phase DC power)

Answer:

3-phase AC power Question 23: 14. What factors determine the amount of voltage produced by a generator? What is the relationship between the factors and the voltage?

Answer:

• II and III (Number of Turns, Speed of Rotation of Rotor, Strength of magnetic field)