And by the same computation, 1400 watts converts to about 100
amps off the alternator. Wonder how many alternators are rated for
that kind of output - they also have to cater to other things like
lights, blower, a/c clutch, ignition, sound system, and so on.
But the alternator would typically have efficiency of 85% plus, and
the fan runs cyclically ( rarely continuously ) so things are not all
that bad.
The mechanical fan at high speeds would draw very high amounts of air
and could result in quicker cut off if it is electromagnetic; but
very often, at such high speeds, the vehicle's ground speed would be
sufficient to give air flow and the fan may not really be needed at
all. I have actually driven about 300 km without a fan ( it broke !
) without any problem.
If I remember right, the power drawn by the fan is proportional to
the cube ( 3 rd power ) of the rpm.
In my opinion, the thermostatic clutch fan is the best choice in
terms of energy efficiency, but then no mechanical fans can be used
on transverse mounted engines, unless we use some weird scheme like
the Peugeot 305 where the belt is twisted into all kinds of shapes in
all dimensions to make a fan run off a tranverse engine. ( Ask some
one who has had to change the belt on a 305 ! ).
jb
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J.Balamurugan Phone: +91 (431) 552281
Computer Support Group FAX: +91 (431) 552133
Regional Engineering College jb@rect.ernet.in
Tiruchirapalli 620015
INDIA
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