How to stop loud electrical whine from SURTA1500XL

[Anonymous user]

I just got a new SURTA1500XL and whenever it is on, it makes a (not extremely loud but very noticable) high pitched whine even when there is no load. The sound constantly shifts making it really annoying. If I power on load devices, the noise changes around (usually becoming more of a buzzing sound with increasing load) but the volume is constant.

The sound isn't the alarm -- the alarm is a lot louder and cleaner sounding.

It isn't the fan either -- if I shut the ups off, the whine stops but the fan keeps going, and the fan is an acceptable low quiet sound.

The battery reached 100% charge a while ago but the sound hasn't changed.

The light 'Site Wiring Fault' is not lit.

I know a double conversion ups has to be 'always on' but this sound seems worse than what I hear when my line-interactive ups 'kicks on' during a power failure (can't confirm this though since the old UPS died).

Is there anything I can do to make it stop? Any diagnostics I should do on my house wiring?

Barring that, should I RMA the unit? Would a replacement be likely to not have this problem?

Or is it normal and unavoidable?

edit: I just noticed that when my laptop is connected to the UPS, the sound instantly gets louder when I scroll in my web browser. I can make the UPS play a tune by scrolling up and down quickly.

[BillP]

This UPS should not sound any different than a line interactive UPS while is online or on battery so if it is noticeable like that, sounds like a replacement may be in order via RMA since it appears to under warranty.

[Anonymous user]

High frequency inverter (AC to DC to AC conversion) noise - goes hand in hand with the internal design/architecture of this model of ups...could be that the ups mainboard is coupling the vibration to the UPS metal chassis which could amplify the sound. That the sound changes as you scroll up and down on your laptop is not entirely out of the ordinary - brightness level changes on your screen plus increased GPU / CPU activity to change the image / load fresh web pages would cause more or less juice to be drawn from the UPS by the laptops' power supply / adapter, increasing the load on the UPS and its inverter stages incrementally which can modulate the "whine". There shouldn't be any need to do anything about it unless your ups shows an actual fault , in my opinion.

[BillP]

I feel like if its loud enough to distract you or even hear over the phone, its not normal.Also if its different than the alarm, but just as loud, it doesn't sound right. These are intended to be installed in a data center/server environment so you may 45 dBA per the technical specs (http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SURTA1500XL) but to me, what you were describing is not normal if it was louder than your average high end computer or server, even when it has a load.

[Anonymous user]

I got out my SPL meter and the sound does appear to be just under 45 dBA but I guess the grating-ness of it makes it seem louder than it is.

I was able to find another UPS of the line-interactive type to do a side by side comparison and while the fan of the SURTA1500XL is actually quieter, the whine is definietly louder even with a fully charged battery and no load.

[Anonymous user]

I did an RMA and the new one seems to be slightly quieter but still more loud than I'd like, especially since the sound seems to get louder with a bigger load.

This makes me think that it's not defective, but another poster says he has a similar sound issue with only 3 out of 4 units of this model:

  Re: SURTA1500XL electrical buzzing sound

So maybe it isn't normal, but just a very common problem?

I thought of exploring soundproofing options but Powerchute doesn't seem to have the temperature montioring features I'd need to make sure I'm maintaining adequate ventilation.

[BillP]

AP9631 UPS Network Management Card comes with an ambient temperature sensor that could maybe help you with the enrivonmental part.

[BillP · Accepted solution]

Excellent point regarding a UPS' intended installation environment!  I have my unit installed in a home theatre environment and I hear it all the time.  If I don't hear it I would get concerned