LQB said:
plutronus said:
Good quality properly designed AC inverter power-modules don't leak multi-spectral power-density noise into AC power-mains, so its somewhat unlikely that a GSA supplied public school would likely use cheap Oriental AC inverters that do.
Not true. Even the more expensive "pure sine wave" inverters are very noisy compared to the generator/motors at the power plant. And this high frequency noise is easily measured. Only the analog motor/generators are truly pure sine wave - the solid state inverters are only approximate sine wave, and this results in high frequency noise that couples into any grid connected to it.
Hi,
I'm trying to be patient about this subject, as its obvious that there is a lot confusion regarding it.
>Not true. Even the more expensive "pure sine wave" inverters are very noisy...
Not intending to be rude or argumentative, but you've been misinformed by someone.
In the context of this discussion, there are essentially three types of electrical/electronic power-supplies:
1) batteries, (chemical current production), typically least noisy of the three types presented in this list,
2) switch-mode power-supplies, --DC to DC, DC to AC, AC to DC, AC to AC, --small, efficient, typically inexpensive, and if there is little or no filtering used, they can be noisy or not depending on design,
3) linear-mode power-supplies, -- AC to DC, DC to AC, large, typically not too efficient, typically expensive. Inherently least noisy of the active component power-supplies. It was this class I cited.
Re; Noise, there's lots of different types of noise, exactly what it is in the minds of laymen, well its a guess. Noise to me is anything that causes interference or systems degradation.
>..compared to the generator/motors..
In the mid-1800s generators were replaced by Nikola Tesla's invention of the alternating-current AC alternator. Municipal power production facilities do not use generators to produce mains power. But I know what you meant although you named oranges to describe apples, and you are being specific.
>...the solid state inverters are only approximate sine wave...
Not all sine-wave inverters, solid-state or otherwise are switch mode or use synthesized sine-waves. Take a sine-wave oscillator (one [solid-state] transistor, analog, such as a Wien Bridge arrangement), put its output into an analog (linear) power-amplifier, drive a step-up transformer and you've got a linear, sinusoidal wave form DC to AC inverter with no high-frequency ringing...no switching noise and no need for filters. Clean AC power. Linear is typically more expensive than switching.
So, yes, there are commercially available, specifically and authentic, 'full sine wave', not synthesized, not digital, not DSP, not switched, not stepped, not pulse-width-modulated, but are genuine sinusoidal linear waveform DC to AC inverters. As I said before, these are generally more expensive, and they are generally a little more difficult to locate, amidst all the marketing lies being proferred by some unscrupulous manufacturers. And they are not noisy in the sense that the 'dirty' power folks think of as being noisy.
>And this high frequency noise is easily measured.
I suspect that you misunderstood my point. I did not say that switch-mode power-supplies were high-frequency un-measurable. I said, that Boltzmann noise is difficult to measure, and I mentioned it simply because its in everything and there is nothing anyone can do about it but the yakkers are yakking about the little things too.
>and this results in high frequency noise that couples into any grid connected to it.
For some switched-mode, poorly designed power-supplies this is true.
Merry Holy-Days to everyone and family..
plutronus
ET Investigator
