RC phase shift

[Kevin Weddle]

Go here www.smartdev.com/pdf/ac_power.pdf. The graph says the fifth harmonic is about half the voltage.

Filtering out large magnitudes not only affects the waveforms appearance, it affects the amplitude. I see it very good when I apply superposition theorem.

 

[audioguru2]

Kevin,
Your article says and shows that the total harmonic distortion of the electrical voltage into homes is only 3.5%. The 3rd and 5th harmonics are only 1%.

They have a graph on page 2 with the 3rd and 5th harmonics at more than 50%, but the voltage scale is in decibels (100dB full scale) so they are at only 1%.

View attachment 40277

 

[Gazza1]

Filtering out large magnitudes not only affects the waveforms appearance, it affects the amplitude. I see it very good when I apply superposition theorem.

You need to step back about 50 yards, harmonics are not just added to the fundamental.


PT=(PF + P 3rd harmonic2 + P 5th Harmonic 2 + P 7th Harmonic 2.........)1/2

I really don't mean to be rude but I think you are completely missing the point here, harmonics do not affect the value of the fundamental portion of a signal, they are additive but in a bad way. They are adding "distortion" to the signal.

The fundamental frequency is the only part of the signal that you want to use. The harmonics are undesirable side effects created by non-linear loads.

Here is a bad analogy:

I have a rock, the rock grows moss due to the environmental conditions surrounding it, I scrape the moss off.

Rock = fundamental
moss = harmonics
environment = type of load/power grid

 

[Kevin Weddle]

They have a graph on page 2 with the 3rd and 5th harmonics at more than 50%, but the voltage scale is in decibels (100dB full scale) so they are at only 1%.

Okay I see, what I thought said voltage meant decibel. The harmonics don't even exist.

 

[Kevin Weddle]

[harmonics do not affect the value of the fundamental portion of a signal

No, but if the harmonics are of higher magnitude, filtering them out will reduce your composite significantly. It doesn't mean your fundamental is reduced, but the composite is reduced.