re: " I do not trust claims of a true sinewave inverter for $50! ! Copper and
iron required for the output transformer "
None of these inverters is close to the old "static" inverters built over 40
ago using Germanium transistors that weighed in at 30 to 100 pounds depending
on rating. I had a 1,000 watt 12 VDC to 110 AC 'static' inverter of that nature
and it was a BEAST. They used ferro resonant techniques to achieve a sinusoidal
Today, they chop at a high frequency, vary the pulsewidth, invert with an
and then filter to arrive at something close to the shape of a sine wave.
This is as opposed to the units which provide a 60 Hz rectangular pulse
positive then negative (with dead time in between) which works out
to be close to 120 V RMS and ~ 150 V pk when actually measured with an O-scope
whereas a real sinewave has a peak of ~ 170 Volts, a smooth continuous shape
no waveform dead time.
On Monday, December 16, 2019, 6:44:53 PM CST, David Eckhardt
BTW, it is not the least expensive unit. I do not trust claims of a true
sinewave inverter for $50! ! Copper and iron required for the output
transformer at 300-watts can not be sourced responsibly for that price,
even in China. If I remember, my inverter was 'around' $250. But, it is
I checked those at Harbor Freight in the $50 range that claimed to be clean
and pure sinewave before buying the referenced unit. They were as dirty as
you might imagine and not massive enough to have a real copper and iron
transformer on the output at 120 vac.
Dave - WØLEV
On Tue, Dec 17, 2019 at 12:38 AM David Eckhardt <firstname.lastname@example.org>
> It is a:
> GO POWER <www.gpelectric.com>
> 1-866 247-6527
> Power Inverter 300 watt DC to AC
> Model: GP-SW300
> Since it is made in China, your mileage may vary. However, mine is pretty
> clean. If I frisk it within a couple of inches with a B-Dot probe (loop),
> I can find a few switching emissions, but pretty low. Both the DC input
> and the AC output are pretty clean - they know how to do decoupling. The
> output is transformer coupled at 60 Hz. I may have gotten this from
> Amazon, but I do not remember - confidence on that statement is about 40%
> 😊 It is a true sinewave inverter.
> I took pictures of the label, but this group strips images from emails.
> On Mon, Dec 16, 2019 at 11:01 PM MICHAEL ST ANGELO <email@example.com>
>> Which brand inverter did you buy?
>> Mike N2MS
>> > On December 16, 2019 at 3:53 PM David Eckhardt <firstname.lastname@example.org>
>> > I installed a 'True Sinewave' 300-watt inverter in our Airstream. It
>> > not produce any objectionable RFI. It would even pass the EU
>> > specifications for conducted harmonicds of 60/50 Hz. However, when I
>> > a loop of the RG-58 feedline around our solar panel, that couples CM
>> > Dave - WØLEV
> *Dave - WØLEV*
> *Just Let Darwin Work*
> *Just Think*
*Dave - WØLEV*
*Just Let Darwin Work*
RFI mailing list
RFI mailing list