Posted by RDavis on Monday, June 18, 2001 at 9:20PM :
In Reply to: One problem with electric water pumps... posted by Brian in Oregon on Monday, June 18, 2001 at 11:39AM :
There seems to be a misconception by some , that I believe an electric waterpump and fan can be operated without consuming any power from the engine. It takes roughly 8hp to turn a fixed fan, the fans wind resistance increaces with engine RPMs. An alt. does not need 8hp from the engine to generate the current needed to run an electric fan and(or)waterpump motor, thus saving hp. The electric fan motor is usually controlled by a thermostat and runs only when needed, thus saving more hp. As you correctly stated, the fan is not needed at highway speeds. If someone checked it out further, it might be possible to control the waterpump motor with a thermostat temp. unit as with the fan, as no water circulates until the mechanical thermostat opens at the block.
The energy needed to turn the alt. against the magnetic generating resistance caused by the current draw of these two electrical devices, is far less than the mechanical energy required to operate the manual equivalent or factory pump and fan.
Electric fans come in a variety of sizes and CFMs and electric waterpumps of today are advanced enough and advertised to run on the street,no longer,"just for drag racing". The battery is basically for starting,the recharging and electrical accessories are run off the alt. If there is no current draw, there is virtually no resistance when turning the alt. So, resistance and power lose are relative to current draw and these two motors don't draw that much current. By all the negative comments, it seems some just don't want it to work or be true?
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