wb 3-5-15

Card Set Information

wb 3-5-15
2010-03-07 21:52:06

Power Harmonics
Show Answers:

  1. Harmonics are voltages and current disturbances that can also be represented by sine waves, but are at different frequencies than the fundamental 60Hz. T or F
  2. The harmonic frequency is a multiple of the fundamental 60Hz frequency. T or F
  3. Harmonic frequencies can be 35 Hz, 100 Hz, 165 Hz, and so on. Explain T or F
  4. Many of the various harmonic waveforms exist in the power supply at one time. T or F
  5. What happens to the predominate 60 Hz wave form when the many harmonic waveforms are out of phase with each other.
  6. Does a distorted 60 Hz waveform, caused largely by electronic equipment affect electronic equipment?
  7. Name three non-linear types of electric loads, other than electronic equipment, that cause harmonics to propagate back into the electrical power supply system?
  8. Are harmonics a steady-state disturbance or intermittent?
  9. Name at least two harmful effects that harmonic currents play on the power supply system.
  10. How can harmonic voltage and current affect neighboring power supply or telephone circuits?
  11. What is one of the first indications of a problem due to harmonics that a Lineman might come across?
  12. Why are conductors, transformers, and motors subject to heating when influenced by a high frequency component of a harmonic disturbance?
  13. Harmonics reduce the reliability of electric signals that activate meters, relays, powerline carriers, and equipment, such as robots. T or F
  14. Is there a method to test for harmonic interference?
  15. What can be done to limit the effects of harmonics on sensitive loads?
  16. Large customers with big power-quality problems. can arrange to have a "custom power" supply. T or F