Power consumption -- real vs actual

Matthew Geier matthew at acfr.usyd.edu.au
Mon Apr 5 19:01:51 CDT 2010

John LLOYD wrote:
> The nameplate rating, used for electrical safety, is 7 amps for an R710 (100V to 120V).
> The power supply rated capacity is 870W (for the high-output version).
> The enterprise power calculator dell.com/calc  says input power is 431 watts, maximum 578 watts.
> Open Manage reports power consumption (at idle) is 252W.
> Now, with this surplus of numbers to choose from, I have a few concerns.  
> First, the enterprise calculator shows maximum (578) less than power supply capacity (870) which is a good thing.
> But, second, the power supply capacity is more than rated input which is 7A * 100V=700VA.  What is the basis for the current rating on the nameplate?

 Watts != VA

 I don't know what the 'Power Factor' is for a  R710 power supply so 
can't check the figures line up.  Generally the Watts rating is smaller 
than the VA rating. 7A x 100V is Watts not VA, so the fact that it's 
lower than the rating on the power supply would be correct if the power 
supply sticker is VA and not watts....

 Being in a 230/240 country creates other issues for us - things that 
come with 15A line cords as on 100v they draw more than 10A thus need 
the higher rated cord. On 230v they are below 10A so don't need the 
higher rated cord/socket, but we have to use a 15A outlet anyway or 
change the plugs on the supplied cords :-)

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