Weird noise from PSU(coil whine?) wehn AC inverter works

Pantelhs Xirouc

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Apr 24, 2013
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hello. in my car i use, a modified sine wave to produce 220v ac. inside the car i run a normal desktop PC, with its PSU. the problem is, as soon as i turn on the inverter (no matter if the PSU is on , or off ) the psu makes a strange whining noise... not to mention that, when the pc works, it has allot of noise in sound.

(To solve that, i have cut the ground wires from the psu to inverter)

Any idea what could be causing this? cause i want to leave the inverter Always on, to remotely start the pc, but this sound makes me fear something is going on. would a pure sine wave solve it? or maybe a new PSU?
 

Attila Punar

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Apr 24, 2013
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I am no expert on this but usually the whine noise is because of too much power to the unit.. its typically a capacitor that makes that "whine". I remember back in el class.. we would overload capacitors till the exploded (just a little poof... fun nevertheless) and they would whine till they exploded, getting louder and louder. Is there anyway to turn down the amperage output? that might help.
 

Pantelhs Xirouc

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Apr 24, 2013
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C++:
[quotemsg=10712991,0,1308360] Is there anyway to turn down the amperage output? that might help.[/quotemsg]

well, i dont think thate the PSU's output has anything to do, since the sound is also being heard when the pc, AND the PSU are turned off... maybe its some AC, i could cut with a low/ high pass filter?
 

Attila Punar

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Apr 24, 2013
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when you turn the inverter on power goes to the psu whether its turned on or not. But i could be wrong, like i said I'm no expert... try to plug it into a wall outlet and if it doesn't make the sound then I am almost certain that its getting too much power.
 

Attila Punar

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Apr 24, 2013
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come to think of it... is it only making the sound when the car is running? if that's the case it might be because your negative is taken off the chassis of the car... you might want to try to take the power straight from the battery.
 

Pantelhs Xirouc

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Apr 24, 2013
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i am taking straight from the battery (e second battery, isolated from first, just for the pc). i will check about if it makes when car is on or off . BUT, if i remove the vga cable of the monitor, then the speakers start buzzig ( with pc turned off) , and you can see a 0.2V AC in the 12v rails of the PSU...
i dont really have a problem for the sound. my only concern, is , if it could do harm to the pc, leaving the inverter on, for hours (Even days) without the pc running.

 

Attila Punar

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Apr 24, 2013
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i have no experience running a PC on a car battery but i would say that the whining sound isn't good (something is getting ready to die)... try to plug the PC into a wall outlet and if it still makes the sound it could be any part in the computer with capacitors... and if it is one of the parts i suggest you troubleshoot and find it asap because depending on the part it could make other parts go bad when it goes...