A short "Get started" for the demo:
Before you run, you should go to “Phase Configuration” under “Harmonics” and select “Single phase”. That is so that you do not get confused by several vectors.
You should also deselect all boxes under “Show harmonics” so that you do not get lots of harmonics to disturb you.
You may have to click the “Clear Graph” button under “Animation” and perhaps also “Run/Stop”. The box “Angle L1” shows the actual angle (L1 means phase 1 in the grid) from starting position. The angle is reset after 360 degrees. You can enter any angle in that box to get a new vector angle. You can also use the + and – keys to rotate the vector. Just experiment away!
When you feel like you want to know what a three-phase system looks like, you can go to “Phase Configuration” under “Harmonics” and select “Three phase”. There are also two two-phase options. The 90 degree option is what Tesla used for his first induction motors. The second system is sometimes still used in rural distribution – and also by some railway companies.
You can add harmonics to your liking. Just check the boxes and see what happens. The amplitudes of the harmonics are inversely proportional to their numbers. That is, third is 1/3rd and eight is 1/8th and so on.
The “triplenes” are interesting. They are always in-phase (pointing in same direction) with each other. That means that they do not cancel when added. They work together to produce a current if a load is connected between phases and neutral. Checking the box “Show sum” produces a black dot that shows the sum of all three voltages. As you can see, the sum of three phases without any harmonics is zero – the dot is staying in center of the system. If you add harmonics, you will see how the dot (the sum) starts moving around. One special case is when you have only the third harmonic activated. You will then see how the sum moves around a lot and that the projected wave-form to the right has a component that has thrice the frequency of the fundamental. This is what heats the neutral if you have lots of (third harmonic) distortion in your system. Ninth does the same thing. And so does sixth, but you should never have much of that. Even harmonics are not only unusual, they are also harmful.
There is audio as well! Not “to scale”. A 50 or 60 Hz hum isn’t heard very well through the PC speaker, so Lars took the frequencies up a bit so you can hear what happens when harmonics are added. Press “Play” under “Sound of L1” to listen. There will be a few seconds of silence while the program generates the wav file, which is then played through the speaker. Adding more harmonics produces a “richer” tone.
Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...