I did science.
Fig. 1 TEST OBJECT, MEASUREMENT INSTRUMENT, AND POWER SUPPLY ARRANGEMENT.
DIMPLEX desk fan type GDCDF30 TMB. Rated 220-240V - 50 Hz, 40 W.
Fig. 2 TEST OBJECT NAMEPLATE
Efergy plug-in power meter type EMS-AU. Wattmeter accuracy ±2% or ±1W.
Fig. 3 DETAIL OF MEASUREMENT INSTRUMENT
Fig. 4 MEASUREMENT INSTRUMENT NAMEPLATE
Speed setting Power (W) Power factor
0 0 W -
1 24 W 94 %
2 29 W 100 %
3 35 W 100 - 97 % (flicks between these two values)
All values read off after fan was left to run on the speed setting for one minute.
The conclusions of this study are as follows.
Rated power of 40 W is approximate.
The settings 1, 2 and 3 do not give a linear decrease in power
Note, I do not have the means to measure the work done by the fan on
the air, nor the output airspeed, so I cannot speak as to the total
efficiency of the fan in terms of electrical energy converted into