| I'm probably wrong on the technical reasons specifically (my motor experience is limited to robotics and rc cars), but its only recently you could buy 29-35 watt ceiling fans due to the use of DC motors: http://www.ceilingfan.com/35-to-50-watt-ceiling-fans-s/1647.... http://www.hansenwholesale.com/ceilingfans/reviews/emerson_m... Averages currently are 75 watts and up to 100 for typical sizes. http://energyusecalculator.com/electricity_ceilingfan.htm You can google up articles from the early 2000s were it was conventional wisdom that the fan ran 100 watts. I did read a bit about motor design but I can't find it now, but clearly the differences in wattage are real. I believe the newer ones are brushless DC vs the single phase induction of old. I imagine newer fan design helps too. This Kensgrove is a whopping 72" but with a DC brushless motor. 31 watts on the highest setting. http://www.homedepot.com/p/Home-Decorators-Collection-Kensgr... Cheaper 56" at 35 watts: http://www.homedepot.com/p/Home-Decorators-Collection-Breeze... This ultra efficient 56" phase induction motor design still uses nearly twice the power of the DC motor! http://www.homedepot.com/p/Westinghouse-Industrial-56-in-Ind... |
> newer ones are brushless DC vs the single phase induction of old. I imagine newer fan design helps too.
Yes, this is the advance in drive circuitry that I referred to - same with the "DC motor" fans. It's still a fact that at the current consumer design point, adding more copper to the windings will increase weight, efficiency, and longevity.