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What follows is a plain HTML version of the Quiz.
All the question's and answer's in this quiz are found in Tom Henry's book, "Transformer Exam Calculations".
1. What is the power factor of a 7460 watt load connected to a 240v 1ˆ½ source that draws 50 amps?
- [ ] 1.6
- [ ] 82%
- [ ] 62%
- [ ] 78%
2. The iron core of a transformer is generally made of laminations rather than a solid iron core and as a result .
- [ ] oil can penetrate the core easier
- [ ] eddy currents are reduced
- [ ] the voltage ratio is higher than the turn ratio
- [ ] less wire is needed in the windings
3. In a transformer, the induced voltage per turn in the secondary winding .
- [ ] will always be less in the primary in a step-up transformer
- [ ] is one-half that of the primary winding
- [ ] will always be more in the primary in a step-down transformer
- [ ] is equal to the induced emf per turn in the primary winding
4. A transformer has a 3 to 2 ratio. Its primary winding is designed for 240 volts. The secondary voltage of this transformer is volts.
- [ ] 215
- [ ] 160
- [ ] 115
- [ ] 120
5. At what power factor is a single-phase system operating at when the wattmeter reads 2000 watts, the voltmeter reads 230 volts, and the ammeter reads 10.1 amps?
- [ ] 89%
- [ ] 72%
- [ ] 86%
- [ ] 1.16%
6. What is the true power of a 10,000 va load, power factor is 85%, single-phase 230 volt?
- [ ] 8500 watt
- [ ] 11,764 watt
- [ ] 1955 watt
- [ ] 2500 watt
7. In an AC circuit the ratio of the power in kilowatts to the total kilovoltamperes is the .
- [ ] load factor
- [ ] demand factor
- [ ] diversity factor
- [ ] power factor
8. What is the turns ratio of a 480/208/120v three phase transformer?
- [ ] 1/2
- [ ] 4/1
- [ ] 2/1
- [ ] 480/208
9. What is the turns ratio on a three phase 480/240/120v transformer?
- [ ] 1/2
- [ ] 2/1
- [ ] 3/1
- [ ] 4/1
10. In a 3ˆ½ system with a 4-wire, 208/120v, there exists:
- [ ] 3ˆ½ 208v, 1ˆ½ 120v, and 1ˆ½ 208v
- [ ] 3ˆ½ 208v, 3ˆ½ 120v, and 1ˆ½ 208v
- [ ] 3ˆ½ 208v, 3ˆ½ 120v, and 1ˆ½ 120v
- [ ] 1ˆ½ 208v, 3ˆ½ 208v, and 3ˆ½ 120v
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