BR1000i with cause strange sound to PSU

[Anonymous user]

Dear, APC team

I just bought APC BR1000i and I'm not sure about something to ask.

When common use on AC power it's ok have no problem but when it switches to

DC power it have sound from my power supply (it may electrical noise) it quite

loud and I try on new power supply but it still have that sound.

I wounder that it's have problem or not?

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my power supply that tested :
1. ThermalTake ToughPower 750w (80PLUS)
2. iCute Titanium Pro 650w (80PLUS)
3. Tagan BZ 600w (80PLUS)

it have the same sound, quite loud.

on full load it around 400w by using cpu and vga burn test program
(Othos + Furmark)


Thank you

Message was edited by: kamikazekao

[BillP]

the BR1000I outputs a step approximated sinewave while on battery. a lot of higher end power supplies may have trouble with this and require a pure sinewave for noise-free operation.

i am not 100% sure what exactly causes it inside of the power supply but that is what it sounds like to me.

a similar issue [was discussed here|http://forums.apc.com/spaces/5/smart-ups-symmetra-lx-rm/forums/general/4711/symmetra-communications-...] which may also provide some more information.

[Anonymous user]

great thank, that helpful.


after read the thread follow link that you post, i think the sound it from step sine wave (all Back UPS series)

with APFC PSU but one thing i'm not sure, does it effect to APFC PSU lifetime?

[Anonymous user]

Step aproximated sinewave, rectangular, triangular, or any highly distorted kind of sinewave is not what the engineer of the components used inside the PSU is expecting, the PSU is designed with a perfect sinewave in mind, but since the small UPS units are only made to keep your equipment running for a few minutes at a time, IMHO the reduction of lifetime is negligible. If you were to run your PSU 24/7 365 days a year on this highly distorted wave, your PSU wouldn't last for as long as its manufacture expects it to last since distorted waves can have the potential for making the PSU run a little bit hotter and the vibration caused by this rough wave will put a bit of strain on some components.

[Anonymous user · Accepted solution]

thank you rau that make sense. very clear