Hi Chris:
The APC RS1500 uses what they call modified sine wave, but I call modified square wave, i.e. it's a square wave with a
couple of parts that are at zero volts.
Don Lancaster promoted "Magic Sinewaves" where a pulse modulated waveform drives an H-bridge. The leading and trailing
edges are determined using the idea of FFT so that all the harmonics up to some number (typically 9 to thirty something)
are zero. There were also 3-phase versions. But he no longer sells any hardware.
PS I'm looking for a source of 3-phase 400 Hz 115 VAC to power a North Finding
Gryo.
http://www.prc68.com/I/WildARK2.html
--
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.
-------- Original Message --------
Yes, "ferroresonant" is also called CVT. Typically rather than buying
just the transformer you buy a box that has one in it but also some
other components to clip spikes (some MOVs) and and LC low pass
filter. I know it seems a saturated core might produce a non-sine
wave but current CVTs have very low distortion.
The other option is an on-line UPS, one that always runs off the
battery. These are expensive if you need a good sine wave output.
The UPS has an output stage not unlike an audio amplifier. Not nearly
as efficient as MOSFET switches. (question: I'd guess that modern
versions would be designed with class-D output stages and have decent
power efficiency??)
The best solution is what the phone companies did. The telco style
equipment, like computers and such runs off 48VDC. and batteries are
connected in parallel from a "battery room". If designing your own
GPSDO, it should be built to run of 12V battery power.
For AC the best solution is a motor generator. Basically an iron
flywheel rides out any small dropouts in the utility power. They had
one for a mainframe computer at a place I worked at a long time ago.
But only that one output 280V at 400Hz as the computer required 400Hz
power.
On Mon, Jul 25, 2016 at 2:43 AM, David J Taylor
<david-tay...@blueyonder.co.uk> wrote:
Chris,
Do you mean like these:
http://www.aelgroup.co.uk/products/agt.php
I have an old 75W unit somewhere....
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