UPSes that do not make a clen sine wave are cheap garbage, period. Cheap was the key factor in design, and the quality of the output power is junk.
Super. All loads are SMPSs. Nothing else exists.
I guess you're too old to have ever seen a VFD.
Sure. Chinese knock offs of knock offs will surely have excellent noise filtering and work to to all claimed specs all the time.
don't tell phil alison. garbage UPSes are perfect for all applications.
Cydrome Leader writes Bullshit : =========================
** Yawnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn....... ** Insane drivel.UPSs and DC inverters are sold for PARTICULAR types of use. Modified sine waves types are very good for many uses, from lamps to TV sets. Horses for courses.
** I had a DIY design for one published a national electronics magazine. Specially engineered for multipole, synchronous motors as used in hi-fi turntables. Perfect sine wave output. Tested the prototype using a 120mm square AC fan....... Phil
It does get up to voltage but the inverter buzzes and then after 2-3 sec trips off with an overload warning.
That is normal though, that's the core job description for VFDs.
I've done it many times during power outages, mainly to bridge the time until I got the generator schlepped around the house, cables laid, fueled up and started. However, this was a cheap camping inverter. Works.
Well, the pickens are already super-slim to non-existent so I can't be choosy. Looks like I'll have to build my own. Not a problem but I don't want to have yet another project.
BTW, when I tried "mock VFD" with a generator and a big audio amp it worked beautifully and the fans also ran with much less buzz.
Stupider than Anyone Else wrote: ===========================
** VFDs are intended to be used with specific classes of AC motor and nothing else. Those with expertise may find other safe uses. AC voltage and frequency are reduced or increased in * proportion* to to avoid any overheating.** Some AC fan motors run quite hot - saw a large outdoor, pedestal type do that recently. The motor overheated and shut off at low speed settings due to inadequate internal air flow. However it worked perfectly with my Variac.
Fixed it by opening up the slotted rear air entry and fitting a steel fan grill instead.
...... Phil
Joerg wrote: ===============
** Might need a series RC snubber across the output of the inverter.The Variac might have emf kick backs when driven by a modified sine wave. Use your scope to have a look FFS
...... Phl
On a sunny day (Fri, 15 Oct 2021 16:00:21 -0700) it happened Joerg snipped-for-privacy@analogconsultants.com wrote in snipped-for-privacy@mid.individual.net>:
Yep, that is how I sometimes drive my 60 Hz cryo cooler. But with a transformer at the outout of the audio amp. Not sure how the transformer would like say 30 Hz... But this thing needs to be driven in resoance, so fine tuning is possible now.
Well, yeah, I can add yet another homebrew project to the large waiting list :-)
It's ok because the voltage is accordingly lower.
Are you freezing a pet rat so it can be brought back to life in 1000 years when medical technology has progressed some? :-)
On a sunny day (Sat, 16 Oct 2021 11:44:17 -0700) it happened Joerg snipped-for-privacy@analogconsultants.com wrote in snipped-for-privacy@mid.individual.net>:
If you say so.
Na, just making liquid air and oxygen for my spacecar to mars, cooling camera sensors to be able to see the aliens, trying to stop glowballworming, basically playing and discovering. Oh I forgot the superconductor, testing home made thermocouples,
Just make sure there isn't a mushroom cloud over your house some day :-)
How about a servo drive board. May need a small amp between drive and fan motor.
.
Joe Gwinn
søndag den 17. oktober 2021 kl. 00.06.40 UTC+2 skrev Joe Gwinn:
it's for controlling RC servos using their pulse width protocol, it's not a for an actual servo drive
On a sunny day (Sat, 16 Oct 2021 13:06:21 -0700) it happened Joerg snipped-for-privacy@analogconsultants.com wrote in snipped-for-privacy@mid.individual.net>:
Not very serious:
Radiation levels are higher now I moved here:
I remember this clip where this Russian guy sits under the head on the wall of a radioactive dear he has shot and the reporter asks him 'Are you not afraid of that radiation?' 'It is good for your cancer he replies.'
Anyways I lost much of my fear for that stuff, have designed and build several gamma spectrometers now.
Of course the tiny Milankovich effect needs the 180ppm to 270 ppm difference in atmospheric CO2 levels between ice ages and interglacials to amplify itself up to a level which will flip the earth between one and the other, plus a lot of highly reflective ice sheets across the northern parts of the northern hemisphere, but Jan doesn't have to know how it works to come to the conclusion he wants.
The snake oil is what Jan is disopensing.
Jan needs an education camp. He'd be endangering humanity if anybody took him seriously, but it is the fossil carbon extraction industry that is the real danger, and the money they spend on suckering gullible twits like Jan and John Larkin so that they can keep on making money out of wrecking the climate for a little bit longer.
The Spanish flu was 1918-19. WW2 was twenty years later. The Spanish flu isn't usually seen as any kind of "trigger".
Actually it is just a bad for you as it is for the cancer, but radiation treatment for cancer concentrates the radiation on the cancer. The head on the wall isn't going to be a directional source.
Knowing the spectrum of the radiation doesn't make it any less damaging.
"Very good" as in somehow magically better than a 50 or 60Hz sine wave?
That's so cute! I bet Mitsubishi and ABB came banging at your door for licensing rights to this new amazing 12 watt VFD.
Yes, but there is more to it than that. And that muffin fan does not require all that much power. The example is of a small version, but there is a spectrum.
Arduino PWN channels can be used to synthesize two-phase variable-speed stepper drive, or three-phase servo drive. The Arduino or whatever makes the PWM, and the servo drive amplifies it.
Joe Gwinn
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