Smart-UPS 2200 RM - regular hum every 45 seconds

[reetp_apc]

This was originally posted on APC forums on 4/20/2016

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Hi,

I have a rack mount 2200 Smart UPS - SUA2200RMI2U

The unit was originally in the UK and now lives in Europe.

Admittedly our electricity supply is not the greatest, hence the UPS, but I have noticed that the SmartBoost is continually cutting in and out.

The LOTRANS value is set at 204v and I set the sensitivity to low but it still seems to flick in for a few seconds every minute or two. Presumably it is seeing a lower voltage than I can see reported. As far as I can see from voltage reporting that I can do the voltage rarely drops below about 220v

I believe EU supply is rated at 230v +/-6v so I would expect to see it down to around 216v anyway.

Batteries are fairly new - within the last 6 months.

Any suggestions on this ? The voltage does not seem low enough to trip the SmartBoost so presume there is another issue.

B. Rgds

John

[reetp_apc]

This was originally posted on APC forums on 4/21/2016

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A side note - I have a domestic consumption meter I thought I would try and see if I noticed anything.

The consumption seems to jump by about 1/2 Kw whenever the UPS goes on to SmartBoost.

Even more perplexed now !

[reetp_apc]

This was originally posted on APC forums on 4/21/2016

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Hmmmm. Really scratching my head now.

Disconnected everything but noticed the humming still continues. Lasts about 3-4 secs every 45 seconds, regular as clockwork.

Happens even with the UPS off - just the power connected. Disconnected batteries etc but still happens the moment the power is connected even though the unit is not 'on'.

Decided to revert back to my trusty old Smart-UPS 1000 - sensitivity set to low via the rear button.

Hooked it all up and connected the power and instantly I get the dreaded hum even before I fire up the UPS. Same pattern. Just quieter than the big UPS.

Clearly something is not right round here. My Fluke shows a steady 235v tonight. Nothing to show that a Low voltage is running SmartBoost.

Guess I need to go round and disconnect the whole house tomorrow and see if something else is up.

What on earth would trigger the UPS to hum for 3-4 secs every 45 seconds ? It is not as loud as when the UPS is on full load when the power is removed.

Any suggestions appreciated.........

B. Rgds

John

[reetp_apc · Accepted solution]

This was originally posted on APC forums on 4/28/2016

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After much hunting the issue was tracked down to a PoE wifi repeater which had an issue. Unit looked OK but clearly had a problem with the power supply