I've heard of some electronic devices having problems running on the output
of a modified sine wave output inverter or small generator that may not have
the best sine wave shape. Would there be any problem using a 1, 2, or 3
stage AC line filter to clean up the output waveform of either, and would it
do any good? They aren't that expensive so adding one to a generator would
seem to me to make a lot of sense. What am I missing?

--
Regards,
Carl Ijames

Oops, meant to post to sci.electronics.design, sigh.

--
Regards,
Carl Ijames

"Carl Ijames" wrote in message news
I've heard of some electronic devices having problems running on the output
of a modified sine wave output inverter or small generator that may not have
the best sine wave shape. Would there be any problem using a 1, 2, or 3
stage AC line filter to clean up the output waveform of either, and would it
do any good? They aren't that expensive so adding one to a generator would
seem to me to make a lot of sense. What am I missing?

--
Regards,
Carl Ijames

"Carl Ijames" wrote in message
news
I've heard of some electronic devices having problems running on the
output of a modified sine wave output inverter or small generator
that may not have the best sine wave shape. Would there be any
problem using a 1, 2, or 3 stage AC line filter to clean up the
output waveform of either, and would it do any good? They aren't
that expensive so adding one to a generator would seem to me to make
a lot of sense. What am I missing?

--
Regards,
Carl Ijames

AC line filters reduce higher harmonics but have little effect at the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

http://www.lamarchemfg.com/productde...rter)/263.html

See pages 13 and 14:
http://www.etmsolar.com/INFO2011/pvc...ers%20work.pdf
"Unfortunately, inductance causes the transformer to have a relatively
low
efficiency (typically about 50%) and the waveform is very load
sensitive."

-jsw

"Jim Wilkins" wrote in message news
"Carl Ijames" wrote in message
news
I've heard of some electronic devices having problems running on the
output of a modified sine wave output inverter or small generator that may
not have the best sine wave shape. Would there be any problem using a 1,
2, or 3 stage AC line filter to clean up the output waveform of either,
and would it do any good? They aren't that expensive so adding one to a
generator would seem to me to make a lot of sense. What am I missing?

--
Regards,
Carl Ijames

AC line filters reduce higher harmonics but have little effect at the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

http://www.lamarchemfg.com/productde...rter)/263.html

See pages 13 and 14:
http://www.etmsolar.com/INFO2011/pvc...ers%20work.pdf
"Unfortunately, inductance causes the transformer to have a relatively
low
efficiency (typically about 50%) and the waveform is very load
sensitive."

-jsw
================================================== =============

Grr, I misread the frequency scale on the datasheet attenuation chart I was
looking at, it was in kilohertz not hertz. I knew there had to be simple
reason or everyone would already be doing it.

--
Regards,
Carl Ijames

"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news
"Carl Ijames" wrote in message
news
I've heard of some electronic devices having problems running on
the output of a modified sine wave output inverter or small
generator that may not have the best sine wave shape. Would there
be any problem using a 1, 2, or 3 stage AC line filter to clean up
the output waveform of either, and would it do any good? They
aren't that expensive so adding one to a generator would seem to me
to make a lot of sense. What am I missing?

--
Regards,
Carl Ijames

AC line filters reduce higher harmonics but have little effect at
the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

http://www.lamarchemfg.com/productde...rter)/263.html

See pages 13 and 14:
http://www.etmsolar.com/INFO2011/pvc...ers%20work.pdf
"Unfortunately, inductance causes the transformer to have a
relatively
low
efficiency (typically about 50%) and the waveform is very load
sensitive."

-jsw
================================================== =============

Grr, I misread the frequency scale on the datasheet attenuation
chart I was looking at, it was in kilohertz not hertz. I knew there
had to be simple reason or everyone would already be doing it.

--
Regards,
Carl Ijames

Here's an idea of what it takes:
https://www.shapellc.com/linetamer-p...ditioners.html

Before stumbling onto the free APC1400 SmartUPS I was looking for a
good, cheap sine wave inverter that would run my fridge, which needs
12A to start, 2A to run. What I found got terrible reviews. The TV
and all my laptops run fine on cheap "modified sine" square pulse
inverters.

The APC would be a good answer if it wasted less idle current and was
more tolerant of AC from portable generators. It has a button on the
back to reduce sensitivity to bad power but that isn't enough.
-jsw

On Sat, 17 Jun 2017 20:22:55 -0400
"Jim Wilkins" wrote:

snip
The APC would be a good answer if it wasted less idle current and was
more tolerant of AC from portable generators. It has a button on the
back to reduce sensitivity to bad power but that isn't enough.

I had one either like or very similar to this that was used in a system
I serviced:

http://www.ebay.com/itm/BEST-MICRO-F...-/291181299549

A lot of the operating parameters could be changed/set by using the
RS232 connection and a terminal program. As you have noted they are
real energy pigs just idling. That whole system got scraped and I had
this unit setting underneath my workbench for backup, playing around. I
gave up on it when the batteries degraded to the point of it being
useless. I'm not sure but it may be possible to set the operating
parameters for input to work with a generator.

It probably should have disappeared with me when I left, nobody else
really understood it... The batteries aren't cheap though and you sure
don't want to leave it plugged in if you don't like high electric
bills

It was awesome to see it working though. Just cut power and watch
everything keep running without so much as a hiccup. It had internal
memory and kept alarms and faults until they got written over. The RS232
port was hooked to a dial up modem. I could call the site up,
interrogate it for faults, alarms, settings... and see where the sites
backup generator (big propane Gererac) had been exercising. Or some
other wacky thing must have happened at say 2:00 am causing the system
to fail and generate user complaints. Very nice.

There was enough equipment cooking at that site that it didn't need
heat. Always nice inside, even on the coldest of winter days.
Summer time was a different story. It took a 3 ton a/c unit to keep it
cool enough so over-temp alarms weren't generated.

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

"Leon Fisk" wrote in message
news
On Sat, 17 Jun 2017 20:22:55 -0400
"Jim Wilkins" wrote:

snip
The APC would be a good answer if it wasted less idle current and
was
more tolerant of AC from portable generators. It has a button on the
back to reduce sensitivity to bad power but that isn't enough.

I had one either like or very similar to this that was used in a
system
I serviced:

http://www.ebay.com/itm/BEST-MICRO-F...-/291181299549

A lot of the operating parameters could be changed/set by using the
RS232 connection and a terminal program. As you have noted they are
real energy pigs just idling. That whole system got scraped and I
had
this unit setting underneath my workbench for backup, playing
around. I
gave up on it when the batteries degraded to the point of it being
useless. I'm not sure but it may be possible to set the operating
parameters for input to work with a generator.


The APC isn't ferroresonant, it synthesizes a sine wave. Talking to it
requires making a non-standard serial cable. I found the commands it
accepts in the manual for 'apcupsd' on SourceForge and wrote a program
to adjust it and display parameters in a small window. The most
tolerant line quality setting still rejects one engine-speed-regulated
generator and frequently reverts to battery on the other.

We've had only short outages since I bought the HF generator so my
upgraded backup system hasn't had serious use. I assume the fridge
will run overnight on batteries which I will partly recharge in the
morning and evening with the generator, and from whatever solar is
available during the day.

I can't fully recharge the batteries inside the house in one day
without generating hydrogen, but can outdoors after the grid returns.
They don't bubble at 13.6V or below, and only fizz lightly at 13.8V.
Supposedly 13.6V gets them to ~3/4 charge quickly and full charge in a
few days. The APC charges at 6A to 13.6V, then hold that voltage as
the current tapers off.

I could put the batteries and APC on a cart and fully recharge them in
the driveway from a generator if necessary but I don't want to attract
thieves. The practicality of that will depend on the weather and how
loud the neighborhood is from other generators. The Predator's sound
at idle doesn't carry very far.
-jsw

Jim Wilkins wrote:
"Carl Ijames" wrote in message
news
"Jim Wilkins" wrote in message news
"Carl Ijames" wrote in message
news
I've heard of some electronic devices having problems running on
the output of a modified sine wave output inverter or small
generator that may not have the best sine wave shape. Would there
be any problem using a 1, 2, or 3 stage AC line filter to clean up
the output waveform of either, and would it do any good? They
aren't that expensive so adding one to a generator would seem to me
to make a lot of sense. What am I missing?

--
Regards,
Carl Ijames
AC line filters reduce higher harmonics but have little effect at
the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

http://www.lamarchemfg.com/productde...rter)/263.html

See pages 13 and 14:
http://www.etmsolar.com/INFO2011/pvc...ers%20work.pdf
"Unfortunately, inductance causes the transformer to have a
relatively
low
efficiency (typically about 50%) and the waveform is very load
sensitive."

-jsw
================================================== =============

Grr, I misread the frequency scale on the datasheet attenuation
chart I was looking at, it was in kilohertz not hertz. I knew there
had to be simple reason or everyone would already be doing it.

--
Regards,
Carl Ijames

Here's an idea of what it takes:
https://www.shapellc.com/linetamer-p...ditioners.html

Before stumbling onto the free APC1400 SmartUPS I was looking for a
good, cheap sine wave inverter that would run my fridge, which needs
12A to start, 2A to run. What I found got terrible reviews. The TV
and all my laptops run fine on cheap "modified sine" square pulse
inverters.

The APC would be a good answer if it wasted less idle current and was
more tolerant of AC from portable generators. It has a button on the
back to reduce sensitivity to bad power but that isn't enough.
-jsw



Most items will run fine on the generator output. The only item in my
place that has any issue is a ceiling fan. It generates a strange buzz
on genny power. I'm guessing it is due to the multiple winding design of
the motor.

--
Steve W.

"Jim Wilkins" writes:


AC line filters reduce higher harmonics but have little effect at the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

And their output voltage is a function of frequency; so when the
generator speed varies. It's also difficult to design F-R tanks
to deliver sine wave output.


--
A host is a host from coast to
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"David Lesher" wrote in message
news
"Jim Wilkins" writes:


AC line filters reduce higher harmonics but have little effect at
the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

And their output voltage is a function of frequency; so when the
generator speed varies. It's also difficult to design F-R tanks
to deliver sine wave output.

They flatten the peaks as the core saturates, which isn't that bad.
The rise and fall is still close to a sine.
-jsw

"David Lesher" wrote in message
news
"Jim Wilkins" writes:


AC line filters reduce higher harmonics but have little effect at
the
fundamental frequency. The components simply aren't big enough to
store much energy and return it later.

Ferroresonant transformers are 60 Hz sine wave filters with voltage
regulation, but look at the weight:
http://www.hammondmfg.com/CVR.htm

And their output voltage is a function of frequency; so when the
generator speed varies. It's also difficult to design F-R tanks
to deliver sine wave output.

They work well enough to have survived on the market, but I don't see
them as a practical DIY project to clean up a modified square wave
(what they really are) inverter unless you find a suitable second-hand
unit cheap and have the gear to test it. My old Sola constant voltage
isolation transformer isn't nearly big enough to start my fridge's
compressor, which draws 12A for 0.3 seconds.

https://public.magnet.fsu.edu/graf/M...Tranformer.pdf
"In general, the Sola constant voltage
regulator must have a capacity nearly equal to the
maximum demand made on it, even for an instant. "

-jsw

"Jim Wilkins" writes:


My old Sola constant voltage isolation transformer isn't nearly
big enough to start my fridge's compressor, which draws 12A for
0.3 seconds.

https://public.magnet.fsu.edu/graf/M...Tranformer.pdf
"In general, the Sola constant voltage
regulator must have a capacity nearly equal to the
maximum demand made on it, even for an instant. "

A friend designed the 3-ph sine-wave-out F-R transformers for
Lorain Products' large UPSi [100 KW & up]. He was the only person
I know who really understood *and could explain* how they worked.

That's a good datasheet, and makes important points; no-load
draws 30+% of full load, they are short-circuit proof, etc.

LPC tested their designs with a LARGE motor, as I recall it was
~4 ft in diameter. They'd hook up way-too-small inverter module
to it, and power it up. The motor would sit there, while the
power module put out its rated current (& hummed mightily.)

If you looked carefully, you'd see the motor twitch, and then
rotate a tiny bit. If you waited, you'd see it move a little
more, finally a full inch of travel. Over many minutes, it
would keep going, gaining speed. After 15-20 minutes, the motor
would get up to 1725 RPM. The module had passed.




--
A host is a host from coast to
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

That is ok - some of us are qualified.

The filter would be just fine. Remember it must pass the current and
handle the voltage and the power rating be all high enough to allow it
to function as a 'passive' filter.

Often high voltage caps across the power line will take out the fast
edges (shunting the RF and middle frequency 'noise'. Remember caps drop
wattage. Some have series resistance and they all have reactance that
drops wattage. Typically L's are present - the inductance of the wire
used and reactance across the lines. If the lines are short - use
inductance or resistance to form the L filter. T's are better.

Martin

On 6/17/2017 5:16 PM, Carl Ijames wrote:
I've heard of some electronic devices having problems running on the output
of a modified sine wave output inverter or small generator that may not have
the best sine wave shape. Would there be any problem using a 1, 2, or 3
stage AC line filter to clean up the output waveform of either, and would it
do any good? They aren't that expensive so adding one to a generator would
seem to me to make a lot of sense. What am I missing?