Hum/Buzz

[jonnytabpni_apc]

This was originally posted on APC forums on 11/5/2008

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HI Folks

I just bought a brand new CS650 from amazon (I live in the UK)

When my UPS runs on battery, it emmits a fairly loud hum/buzzing noise.

Is this normal? Sounds like transformer saturation...

Very little load was being applied (about 70W)

Cheers,

Jonny

[Erasmus_apc]

This was originally posted on APC forums on 11/5/2008

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What is your model and serial #?

Many of our units will emit a buzzing noise when on battery...this is normal. It should not be heard across rooms though. The inverter/battery discharge cycle on back-UPS only starts when the UPS has gone onto battery from a loss of power or other power event, and so the change in noise will be quite apparent.

[jonnytabpni_apc]

This was originally posted on APC forums on 11/6/2008

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it's a Back-UPS CS 650VA 230V

I guess the buzz noise is normal. The buzzing changes a bit like its vibrating and touching something (i.e. it's not the same noise constantly).

Does that make sense?


Cheers

[Erasmus_apc · Accepted solution]

This was originally posted on APC forums on 11/6/2008

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I could see how that description would be accurate...

Can I have an exact model # please? Ex: BK650EI, BK650I, BK650MC (not 230v), etc. etc. and a serial number please? I highly doubt believe Amazon (or it's supported resellers) would sell an old unit labeled as "new" but unfortunately in this world we can never be sure.

Our support team here does not deal with the international units so the most I can do is advise you that the units will make an electrical hum when on battery that differs from the usual "online" noise, and that you could check to make sure the unit provides power on battery and passes a self test. Alternatively, you can check www.apc.com and select your locale-based section for the technical support number for the UK.