In terms of wear and tear as well as efficiency, the electric fan is
superior. As any one is familiar with racing, reducing rotational mass
is the equivelent of taking off two times the weight (at least) of
stationary mass. (IE: ten pounds off each tire = 80 pounds inside car).
In the case of unsprung weight (tires) the benifits are even greater as
the suspension is allowed to work faster, by reducing the weight
reacting to the forces acting on the tire.
This is same scenario can also be applied to the engines ability to
rev. With less rotational mass to accerlerate, the engine is allowed
to rev quicker. Lightened flywheels are the usual way to achieve this.
The electro-magnetic assemlies, which are quite heavy, are constantly
having to be accelerated and decelerated with the revs of the motor,
this is wasted energy.
The electric fan uses no energy when not in use, is stationary mass
when idle (very light in comparison), and very efficient when
considering the efficiency of the combustion engine.
This combined with the added benifits of unloading the pump shaft,
makes the electrical fan the obvious choice. I agree that I neglected
the loading of the fan belt in my initial letter, but without the fan,
belt tension can be reduced consideribly without affecting normal
operation. I've done it myself with no problems.
Take care
Rabin James