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

 

[George Herold]

On Wednesday, January 20, 2016 at 5:35:16 PM UTC-5, Tim Wescott wrote:

On Wed, 20 Jan 2016 11:08:26 -0800, etpm wrote:

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?

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.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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.

 

[Tim Wescott]

On Wed, 20 Jan 2016 11:08:26 -0800, etpm wrote:

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?

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.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Ron M.]

On Wednesday, January 20, 2016 at 8:25:33 PM UTC-6, George Herold wrote:

On Wednesday, January 20, 2016 at 5:35:16 PM UTC-5, Tim Wescott wrote:
On Wed, 20 Jan 2016 11:08:26 -0800, etpm wrote:

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?

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.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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.

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 board. The reverse protection diode was a huge approx. 20 vdc zener aerial mounted in the PA. It had gotten so hot it desoldered itself. Hmmm. Finally called 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.

 

[Tim Wescott]

On Wed, 20 Jan 2016 18:25:25 -0800, George Herold wrote:

On Wednesday, January 20, 2016 at 5:35:16 PM UTC-5, Tim Wescott wrote:
On Wed, 20 Jan 2016 11:08:26 -0800, etpm wrote:

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?

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.

--

Tim Wescott Wescott Design Services http://www.wescottdesign.com

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.

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.

--
www.wescottdesign.com

 

[Tim Wescott]

On Wed, 20 Jan 2016 18:25:25 -0800, George Herold wrote:

On Wednesday, January 20, 2016 at 5:35:16 PM UTC-5, Tim Wescott wrote:
On Wed, 20 Jan 2016 11:08:26 -0800, etpm wrote:

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?

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.

--

Tim Wescott Wescott Design Services http://www.wescottdesign.com

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?

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.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com