Hi John:
> Can you tell me the typical power consumption of a desktop
> VDU. For example a Sun workstation VDU rating plate indicates
> 220-230 V 1.5A. Rather than assume or guess a power factor
> value, what would the power reading (Watts) be approximately
> at 220V for nornal operation ? What power factor value
> would you attribute to a modern desktop VDU ?
I don't understand the question. The third sentence
doesn't want to guess a power factor, but the last
sentence seems to want such a guess.
In order to guess the power, we need to guess at the
voltage, the current, and the power factor.
Current: The rated current is pessimistic and will be
110% or more of the actual current. Furthermore,
the actual current will be a linear function of the
voltage.
Voltage: If the nameplate ratings are quoted properly,
then the rated input current will be at 220 V, not
230 V.
If the manufacturer accounted for 220 - 10%, then
the current is for 198 V.
(If the nameplate includes 120 V, then the current
*may* be the maximum current at 120 V, which will
drastically reduce the value of the power.)
Power factor: Most products today use switching-mode
power supplies. Power factor for SMPS will be in
the neighborhood of 0.6, maybe less.
Power: Using the above assumptions, the power input
should be about:
220 x 1.5/1.10 x 0.6 = 180 watts
or:
198 x 1.5/1.10 x 0.6 = 162 watts
So, my guess would be that the actual power consumption
is between 160 and 180 watts.
Best regards,
Rich
-------------------------------------------
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: jim_bac...@mail.monarch.com
Michael Garretson: pstc_ad...@garretson.org
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
