UPS: Compensating for a high input voltage.

[Colin Johnston]

Hi Paul,
same issue seen at TTL www.ngat.com at birkenhead in liverpool.
At night we were seeing peak voltage spikes on the APC's for the  
telescope computers.
Scottish Power came and put a trace on the incoming power feed and  
the power fluctuations were seen.
In the end they dropped the current output from the substation  
outside the building.
Note you might have arguments with the power company to say the  
fluctuations are within percentage allowed. ie 240v we saw in graphs.

Colin

On 13 Aug 2008, at 10:57, Paul M wrote:

> We seem to get a significant number of these warning messages from  
> our UPS, an APC SUA5000 unit - appended.
>
> I am wondering if this is a problem specific to the Science Park  
> here in Cambridge or just us - is anyone else seeing mains voltage  
> getting very high?
>
> I am worried that there's a risk of damage to our systems. Here's a  
> snapshot graph of power measurements; red line is output voltage,  
> green is mains.
> http://www.mansfield.co.uk/misc/ups01.png
>
> I reckon that what's happening is the power demand from the science  
> park varies hugely and affects the grid's ability to regulate  
> voltage, so after 9pm-ish, the mains voltage rises above the UPS's  
> warning margin. According to my cheapo electricity meter we're  
> currently seeing 236V, which is above the norm of 230V
>
> regards
> Paul
>
> -------- Original Message --------
> Subject: UPS: Compensating for a high input voltage.
> Date: Tue, 12 Aug 2008 21:24:12 GMT
> From: **@**
> To: **@**
>
> Name     : ups01.***.***
> Location : **************
> Contact  : **@**
> http://ups01.***.***
> http://##.##.##.##
>
> Serial # : ##########
> Device Ser #: ###########
> Date: 08/12/2008
> Time: 21:24:10
> Code: 0x010D
>
> Warning - UPS: Compensating for a high input voltage.
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