Hissing UPS
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You are currently reading a thread in /g/ - Technology
I've got m hands on Compaq R1000h UPS.
I replaced old dead batteries and all seems to work fine, except it hisses.
I pinned the problem to the transformer.
Although it's barely audible, it's pretty anoying.
Do you guys had this problem with your UPSes?
I was considering dipping the transformer in polyexter resin under vacuum, but i'm afraid it's not the coils but magnetostriction, so it wouldn't help.
>>54330367
bemp?
>>54330367
Actually, it might.
You could also try tweaking the frequency the inverter works at to shift the resonance.
>>54330367
It's probably just old. Or shit.
>>54331290
This.Scope it if you can.Something as simple as a failing cap could be the culprit.
>>54331353
>Scope it
H-bridge is giving it pretty rough squarish waveform, with a little bti fo ringing on the edges.
Checked all caps, they are good.
I have its bigger brother (R3000h) and it's quieter...
>>54331703
Update, yeah, i recorded it wiht my microphone, sis FFT in audacity and it's one half (20kHz) of PWM driver's frequency (40kHz), so it must be magnetostriction, shame...
>>54331290
>You could also try tweaking the frequency the inverter works at to shift the resonance.
Nopots to adjust the PWM waveform generator. It has some old-ass OTP ROM microcrontroler.
Why do u know so much about this shit
>>54332110
Because it's technology and not the same old "lol vidya game pc build me"
>>54331290
You could tweak the deflector to reverse it's phase polarity and mask our warp signature with dark neutrinos.
>>54332110
It's basic knowledge man.
>>54332321
I already affixed encabulator to pentametric boloid slot, but unfortunatelly it's not reversible.
>>54332400
Actually now that I think of it... what about building a little arduino project to sense the phase of it's 20KHz audio signal and product a sound that is exactly out of phase to cancel it out?
>>54332455
>arduino project
Back in my day, we used just op-amps for that.
>>54332483
no point when an arduino is like $2
http://www.ebay.com/itm/Pro-Mini-Enhancement-ATMEGA328P-5V-16MHz-Compatible-to-Arduino-PRO-mini-/191679508570
>>54332555
Wow, i'm trully amazed by chinese ppl.
Half of the price is shipping.
To the deliver this assembled device for around $1.
I feel uneasy.
>>54332555
>using an arduino to produce a 20khz analog signal
arduinofags need to seriously kill themselves
>>54332816
The project I described is a bit more complex than just making a 20KHz signal. Anyway, a 555 won't give the accuracy needed.
>>54332949
>Anyway, a 555 won't give the accuracy needed.
I doubt that.
It's pretty easy to build a sine generator with 555, it's phase locking with our 'noise' singla what is tricky.
although arudino would help a lot with that, making asimple inverting amplifier with op-amp is way faster and easier than fiddling with derpduino (in this particular project).
Op here btw.
I reassembled the UPS, since it's 750W unit i wouldn't use it anyway with my PC (it barely draws 80W), imma bring my old orvaldi 250W UPS for that.
this R1000h will probably back up power for my nighly backup NAS and other shit like that, hidden in the attic so noise isn't that much of a concern.
>>54332949
exactly where does the arduino and 555 timer fit in to all of this?
>>54333145
Don't worry, younger sutdents find ti easier to use tools they already "know" in place of learnign some basics or new tools.
They, raised in a digital world, use to optmise for time, not knowledge accumulated.
Findign quick (and often dirty solution) for even easy problems, that's how management in corporations work...
>I know how to set up a ADC
>I know how to make a simple DAC from a PWM and RC filter
>Let's simulate this behavior using a microcontroler, will be don ein 30 minutes
= no knowledge gained, they get a raise for delviering 30 mins ahead of time
Instead of:
>Hmm i might be able to use op-amps for this, let's research this
>Problem fixed in 3 hours
= knowledge gained, management angry, they delivered 2 hours short
