All electrical engineers of the world should get together and pay this gentleman a million dollars a month to explain every topic of every course needed for a master's degree. Then, we could retire all other living professors, starting from my lazy professors.
Man, speaking as a person from a non-english speaking country, I must congratulate you for the very paused and clear pronunciation of the words. Beyond that, the high value content and the masterful way in which the subject was explained! Congrats!
I am working in ABB as drives quotation specialist but believe me I have not come across such detailed explanations on THD/TDD and mitigation options... hats off to you sir!
yaskawa is very sincere manufacturer , even in eighties i have seen a yaskawa motor which did not require any regular maintenance at that time compared to other brands . liquid starter never gave trouble for 8 years in a row , and was free from dust in our heavy dusty environment @ a cement plant .
OMG !!! after a long time struggling and searching, this is the only video that answered my question and gave good understanding of it. Million thanks to him. So, nice lecture (but not really the way of traditional lecture though). Once again thanks a lot.
This explanation was so beautifull that I lerned something about harminics mitigation in large power generators. And i was looking for harmonic distortion in audio amplifiers. Great work indeed. Really interesting. Thanks.
"What kinds of harmonics do variable speed drives create? Well, it depends." Now that is definitive for you! How's about this: Just like with other loads, variable speed drives distort the input wave causing harmonics. The ANGLE that the input wave was at when it impacted the distortion determines which harmonics are created and the pattern of harmonics created in the spectrum. This pattern is known as the Harmonic Signature, and the Bullard Harmonic Solution can be used to predict the harmonic signature based only on the angle that the incoming sinusoid was at when it impacted the distortion. This is Law #2 of the Bullard Laws of Harmonics. Different devices (VFD, fluorescent lights, rectifiers, etc) have distortions lurking at various voltage thresholds and when the incoming wave impacts those thresholds, it distorts the wave and the angle at which that happens determines the harmonic signature. God did not anticipate which electronic devices mankind might invent and then devise a set of harmonics for each and every human invention.
Such a phenomenal video. I have more questions now than when I started the video, but that's because the topic was covered so well, that it made me realize how much more I need to know about Harmonics, IGBT's, EMI Filters, etc. I am particularly interested in how the drive provides regeneration @ 21:30 Thanks so much for providing us with such great instructional videos.
A well done work is timeless. 9 year old instructional video and still awesome! The TDD table meant for point of common coupling was indeed used by PQ specialists within load side facilities because they give a good reference point. You just need to be aware of how you interpret the results.
A correction @ 3:00. Not all linear loads draw a sinusoidal steady-state current when the voltage is sinusoidal. As an example, a resistor whose resistance is a function of time (but not of voltage nor current), is a linear resistor, yet it will draw non-sinusoidal current when a sinusoidal voltage is applied. The most accurate and general definition of a linear load/device/system is that whose relation between voltage and current follows the superposition principle.
ok ok, i watched this video 4 years ago and really like this drive harmonics video... however, what new drives are there in 2020, not needing reactors and the like? thanks...:)
