How is the mains power filtered?

I was looking at the power from my generator and there are of course harmonics in the output. I don't know much about harmonics and how they are filtered out so I looked online for information and found that it is not that easy to filter the harmonics coming from the typical consumer grade gasoline powered generator. Things like changing load and generator rpm make it even harder to filter passively. Then I thought about the generators that supply power to the grid and so I checked my power and it is much cleaner (naturally) than the output from my generator. How is this done? Thanks, Eric

Reply to
etpm
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I'm pretty sure that it starts with generators whose magnetic circuits are much more carefully designed to generate nice clean sine waves.

So, basically, some engineer has sweated blood over the shapes of the iron pieces to make sure that the resulting power is clean.

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Tim Wescott 
Wescott Design Services 
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Tim Wescott

I know diddley about how power is generated. But we use to have power "conditioners" in the lab You'd plug in Mains AC at one end and get clean AC out the other... the thing weighted a ton, huge transformer and a gang of power transistors. (I have no idea how it worked...) I only know about it because the fan failed and the power transistors heated up so much that they fell out of the heat sink when the solder melted. I fixed the fan cleaned things up soldered 'em in and it worked.... I wonder if transistors held upside down on the heatsink by nothing but the solder joints was a fail safe idea?

George H.

Reply to
George Herold

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Once had a Motorola Astro Spectra that came in 5 times always with the same problem. I was the lucky 5th tech. Bad RF power amp and blown command boar d. The reverse protection diode was a huge approx. 20 vdc zener aerial moun ted in the PA. It had gotten so hot it desoldered itself. Hmmm. Finally cal led said AFB and it was always placed in a particular firetruck. Behold the answer. Bad voltage regulator on the truck. Man I miss those days.

Reply to
Ron M.

I used to work with a guy who would use resistors as last-ditch fuses, planning on them desoldering themselves.

So yes, I could easily see that being done on purpose.

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Reply to
Tim Wescott

I'm just guessing that the thing was doing some preliminary passive filtering, and then was cleaning up with a power amplifier generating an opposing voltage to the error between what you have and what you want.

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Tim Wescott 
Wescott Design Services 
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Tim Wescott

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