OT - AC Filtering
Archiver
Posts: 46,084
I have a DC to AC inverter that produces a less than ideal 110VAC sine wave.
What should I do to clean that up?
The load is less than 3A. Can I build a simple circuit with a big cap and a
resistor? If so, what kind of values to get a nice, smooth 60Hz sine wave?
TIA!
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
Many people think that history is a dull subject. Dull? Is it "dull" that
Jesse James once got bitten on the forehead by an ant, and at first it
didn't seem like anything, but then the bite got worse and worse, so he went
to a doctor in town, and the secretary told him to wait, so he sat down and
waited, and waited, and waited, and waited, and then finally he got to see
the doctor, and the doctor put some salve on it? You call that dull?
What should I do to clean that up?
The load is less than 3A. Can I build a simple circuit with a big cap and a
resistor? If so, what kind of values to get a nice, smooth 60Hz sine wave?
TIA!
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
Many people think that history is a dull subject. Dull? Is it "dull" that
Jesse James once got bitten on the forehead by an ant, and at first it
didn't seem like anything, but then the bite got worse and worse, so he went
to a doctor in town, and the secretary told him to wait, so he sat down and
waited, and waited, and waited, and waited, and then finally he got to see
the doctor, and the doctor put some salve on it? You call that dull?
Comments
AC Motor Cap would work) across your load. If the load draws 3 amps at 110
VAC then it is approx 37 Ohms (Resistance = Voltage/Current). The Cap
should have a capacitative reactance of at least 5 times that amount to
insure it does not load down the Inverter too much; i.e. 185 Ohm Reactive.
A 10 Microfarad Cap has 265 Ohms, Xc=1/(2*Pi*F*C), while a 15 Microfarad Cap
has 177 Ohms. Unfortunately, if the waveform has a lot of harmonics at 120
and 180 HZ, this won't help too much.
A more robust way would be to hang both a cap and an inductor across the
load with the reactance of both the same at 60 HZ (a parallel tuned circuit
at 60 HZ). This will take some experimentation and be careful......you
might want to put a 3 amp fuse between your load and tuned circuit to
prevent blowing out the inverter in case something gets shorted or is not
the right value. I measured the secondary of a 110VAC/24VAC transformer and
came up with 272 milihenries at 3 ohms DC resistance. To match that you
need a cap would be 26 Microfarad which would resonate with the coil at 60
Hz. That will give you the cleanest waveform.
Original Message
From: "Jeff Abrams" <clavier@b...>
To: "Basicstamps@Yahoogroups. Com" <basicstamps@yahoogroups.com>
Sent: Monday, July 07, 2003 9:31 AM
Subject: [noparse][[/noparse]basicstamps] OT - AC Filtering
> I have a DC to AC inverter that produces a less than ideal 110VAC sine
wave.
> What should I do to clean that up?
>
> The load is less than 3A. Can I build a simple circuit with a big cap and
a
> resistor? If so, what kind of values to get a nice, smooth 60Hz sine wave?
>
> TIA!
>
> ---
>
> Jeff Abrams
> jeff@m...
>
> TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
> TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
> http://www.mazdamaniac.com
>
> Many people think that history is a dull subject. Dull? Is it "dull" that
> Jesse James once got bitten on the forehead by an ant, and at first it
> didn't seem like anything, but then the bite got worse and worse, so he
went
> to a doctor in town, and the secretary told him to wait, so he sat down
and
> waited, and waited, and waited, and waited, and then finally he got to see
> the doctor, and the doctor put some salve on it? You call that dull?
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
noise or distortion in the line becomes noise or distortion on the video and
audio outputs.
I have "ghosting" in the video and an audio buzz that disappears if I run
the PC on clean power.
A square wave is full of harmonics (all odd, of course) that plays havoc
with the stuff that is powered by it.
Chuck's solution is probably the best idea, but I need to digest his
suggestion a bit because I am not too familiar with component-level
electronics - especially AC power - like that.
My experience with caps ends with little electrolytics and I have no real
experience with resonant circuits. I don't have any bi-polar caps or
inductors laying around, either.
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
Original Message
From: Jim Forkin [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=sAosKuXsr6WOSnncFYpybtSNwaZztb77u94SIseaZ1sZ00d-gQHUWRBQQFZi6I0zJkzDY5ZL]jjf@p...[/url
Sent: Monday, July 07, 2003 4:48 PM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] OT - AC Filtering
In reality, a distorted waveform from the inverter is not uncommon. Many
are distorted and some even a square wave which can be a problem. But, if
you have something resembling a sine wave, even with distortion, and it is
the proper voltage, it really doesn't matter for most applications.
Anything including a square wave will light a bulb and most motors will run
fine with distortion. Ac fed into a transformer may produce more or less
voltage on the secondary but in regulated supplies it doesn't matter. The
only problem areas that I see may be timing circuits tied to the frequency
of the ac line and motors which get their speed regulation from the ac
(clock motors). If it doesn't cause any problems it doesn't matter what the
waveform looks like so don't worry about it.
jim
http://www.geocities.com/jimforkin2003/
Original Message
From: chuckirwin43 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=5nVXJxTtjTQqAJU9RpEMqcRg7bgK3YqHzd9EtVtqBZ61HFl0QHCQE-yrVSchoSDryo72W9hJEou5aRIiLEP5nFfEqQ]chuckirwin43@n...[/url
Sent: Monday, July 07, 2003 1:28 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] OT - AC Filtering
You can try putting a 10-15 Microfarad bipolar cap (for AC use, probably an
AC Motor Cap would work) across your load. If the load draws 3 amps at 110
VAC then it is approx 37 Ohms (Resistance = Voltage/Current). The Cap
should have a capacitative reactance of at least 5 times that amount to
insure it does not load down the Inverter too much; i.e. 185 Ohm Reactive.
A 10 Microfarad Cap has 265 Ohms, Xc=1/(2*Pi*F*C), while a 15 Microfarad Cap
has 177 Ohms. Unfortunately, if the waveform has a lot of harmonics at 120
and 180 HZ, this won't help too much.
A more robust way would be to hang both a cap and an inductor across the
load with the reactance of both the same at 60 HZ (a parallel tuned circuit
at 60 HZ). This will take some experimentation and be careful......you
might want to put a 3 amp fuse between your load and tuned circuit to
prevent blowing out the inverter in case something gets shorted or is not
the right value. I measured the secondary of a 110VAC/24VAC transformer and
came up with 272 milihenries at 3 ohms DC resistance. To match that you
need a cap would be 26 Microfarad which would resonate with the coil at 60
Hz. That will give you the cleanest waveform.
are distorted and some even a square wave which can be a problem. But, if
you have something resembling a sine wave, even with distortion, and it is
the proper voltage, it really doesn't matter for most applications.
Anything including a square wave will light a bulb and most motors will run
fine with distortion. Ac fed into a transformer may produce more or less
voltage on the secondary but in regulated supplies it doesn't matter. The
only problem areas that I see may be timing circuits tied to the frequency
of the ac line and motors which get their speed regulation from the ac
(clock motors). If it doesn't cause any problems it doesn't matter what the
waveform looks like so don't worry about it.
jim
http://www.geocities.com/jimforkin2003/
Original Message
From: chuckirwin43 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=uIO5O-Aol140ItHGB43VH_-25u-tG8O1haiFXPsWOkSMbTUQlDdYPcBCaDGrfeZXk3jbgn30PGyxT1H3u5eMN7lU]chuckirwin43@n...[/url
Sent: Monday, July 07, 2003 1:28 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] OT - AC Filtering
You can try putting a 10-15 Microfarad bipolar cap (for AC use, probably an
AC Motor Cap would work) across your load. If the load draws 3 amps at 110
VAC then it is approx 37 Ohms (Resistance = Voltage/Current). The Cap
should have a capacitative reactance of at least 5 times that amount to
insure it does not load down the Inverter too much; i.e. 185 Ohm Reactive.
A 10 Microfarad Cap has 265 Ohms, Xc=1/(2*Pi*F*C), while a 15 Microfarad Cap
has 177 Ohms. Unfortunately, if the waveform has a lot of harmonics at 120
and 180 HZ, this won't help too much.
A more robust way would be to hang both a cap and an inductor across the
load with the reactance of both the same at 60 HZ (a parallel tuned circuit
at 60 HZ). This will take some experimentation and be careful......you
might want to put a 3 amp fuse between your load and tuned circuit to
prevent blowing out the inverter in case something gets shorted or is not
the right value. I measured the secondary of a 110VAC/24VAC transformer and
came up with 272 milihenries at 3 ohms DC resistance. To match that you
need a cap would be 26 Microfarad which would resonate with the coil at 60
Hz. That will give you the cleanest waveform.
Original Message
From: "Jeff Abrams" <clavier@b...>
To: "Basicstamps@Yahoogroups. Com" <basicstamps@yahoogroups.com>
Sent: Monday, July 07, 2003 9:31 AM
Subject: [noparse][[/noparse]basicstamps] OT - AC Filtering
> I have a DC to AC inverter that produces a less than ideal 110VAC sine
wave.
> What should I do to clean that up?
>
> The load is less than 3A. Can I build a simple circuit with a big cap and
a
> resistor? If so, what kind of values to get a nice, smooth 60Hz sine wave?
>
> TIA!
>
> ---
>
> Jeff Abrams
> jeff@m...
>
> TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
> TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
> http://www.mazdamaniac.com
>
> Many people think that history is a dull subject. Dull? Is it "dull" that
> Jesse James once got bitten on the forehead by an ant, and at first it
> didn't seem like anything, but then the bite got worse and worse, so he
went
> to a doctor in town, and the secretary told him to wait, so he sat down
and
> waited, and waited, and waited, and waited, and then finally he got to see
> the doctor, and the doctor put some salve on it? You call that dull?
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
stereo. I too found it was clean when hooked up to "mains" AC.
My solution was to put a "Noise Filter" on the DC side of the Laptop Cord. The
filter is basically a Big DC cap and is sold in the car audio section to help
filter out that noise that the car puts out.
If you have a standard PC with a switching power supply you could hack into the
Mainboard ATX connector and put filtering DC caps on each line. But that might
get really messy. They do sell 12V ATX power supplies! I'd still filter the DC
on the way to the 12v Power Supply...[noparse]:)[/noparse]
Good luck,
Tim
>>> clavier@b... 07/07/03 03:32PM >>>
Well, unfortunately, I am running a multimedia PC on that inverter and any
noise or distortion in the line becomes noise or distortion on the video and
audio outputs.
I have "ghosting" in the video and an audio buzz that disappears if I run
the PC on clean power.
A square wave is full of harmonics (all odd, of course) that plays havoc
with the stuff that is powered by it.
Chuck's solution is probably the best idea, but I need to digest his
suggestion a bit because I am not too familiar with component-level
electronics - especially AC power - like that.
My experience with caps ends with little electrolytics and I have no real
experience with resonant circuits. I don't have any bi-polar caps or
inductors laying around, either.
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
I'm sure the power supply and motherboard already have some sort of
filtering in place.
I don't know that just putting a cap across each supply line is going to do
the trick.
Maybe some caps and a big torroid?
---
Jeff Abrams
jeff@m...
TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
http://www.mazdamaniac.com
If you're robbing a bank and you're pants fall down, I think it's
okay to laugh and to let the hostages laugh too, because, come on, life is
funny.
Original Message
From: Tim Hart [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=VZewKzevQHQn3dKRaK7Yil56_74QKiKKQVtv5T-YTkTJkok0s_KNgwUBlpH5NsdtynxkbARc1v3AvoJyn8Q]tim.hart@h...[/url
Sent: Monday, July 07, 2003 6:09 PM
To: clavier@b...; basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] OT - AC Filtering
I ran into the same problem with a Laptop playing an audio book into my car
stereo. I too found it was clean when hooked up to "mains" AC.
My solution was to put a "Noise Filter" on the DC side of the Laptop Cord.
The filter is basically a Big DC cap and is sold in the car audio section to
help filter out that noise that the car puts out.
If you have a standard PC with a switching power supply you could hack into
the Mainboard ATX connector and put filtering DC caps on each line. But
that might get really messy. They do sell 12V ATX power supplies! I'd
still filter the DC on the way to the 12v Power Supply...[noparse]:)[/noparse]
Good luck,
Tim
at 60 HZ across the 110VAC supply should clean it up quite nicely. If you
need a way to measure inductive reactance, let me know.
Kindest regards,
Chuck Irwin
Original Message
From: "Jeff Abrams" <clavier@b...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, July 07, 2003 19:18 PM
Subject: RE: [noparse][[/noparse]basicstamps] OT - AC Filtering
> Hmm. That is an interesting idea.
> I'm sure the power supply and motherboard already have some sort of
> filtering in place.
> I don't know that just putting a cap across each supply line is going to
do
> the trick.
> Maybe some caps and a big torroid?
>
> ---
>
> Jeff Abrams
> jeff@m...
>
> TURBOCHARGED & INTERCOOLED 2.5 liter 1993 Mazda MX-3 GS
> TURBOCHARGED & INTERCOOLED 1.8 liter 1997 Mazda MX-5 Miata
> http://www.mazdamaniac.com
>
> If you're robbing a bank and you're pants fall down, I think it's
> okay to laugh and to let the hostages laugh too, because, come on, life is
> funny.
>
>
>
>
>
Original Message
> From: Tim Hart [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=y-cq4GNQ8RPtJvrJjPCCiNelwNWlYK0q7JaPZniPpigVeT8KuMxNkadFOKCJVzLqKitxxRZQYCW_aaQH1wA]tim.hart@h...[/url
> Sent: Monday, July 07, 2003 6:09 PM
> To: clavier@b...; basicstamps@yahoogroups.com
> Subject: RE: [noparse][[/noparse]basicstamps] OT - AC Filtering
>
>
> I ran into the same problem with a Laptop playing an audio book into my
car
> stereo. I too found it was clean when hooked up to "mains" AC.
>
> My solution was to put a "Noise Filter" on the DC side of the Laptop Cord.
> The filter is basically a Big DC cap and is sold in the car audio section
to
> help filter out that noise that the car puts out.
>
> If you have a standard PC with a switching power supply you could hack
into
> the Mainboard ATX connector and put filtering DC caps on each line. But
> that might get really messy. They do sell 12V ATX power supplies! I'd
> still filter the DC on the way to the 12v Power Supply...[noparse]:)[/noparse]
>
> Good luck,
> Tim
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>