Thread: Pump Confusion
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Old 27-08-2003, 03:03 AM
Axolotl
 
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Default Pump Confusion

Andrew Burgess wrote in
:


No. The wattage is a maximum value. Throttling the output, for
example, will reduce the power draw.

I do not think this is true. Two elements, pressure and volume, influence
the power consumption of any pump. If you look at Mark's Standard
Handbook for Mechanical Engineers 14-22 thru 14-25 you will find the
formula for centrifugal pump output. Stripped of its more complicated
bits the formula shows that the power required, p = Q*H, where p = power,
Q=volume and H = head. Throttling reduces the volume output but increases
the internal pressure. Essentially throttling the pump has the same
effect within the pump of increasing the head.
AXO