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Unread 11-13-2002, 03:15 PM   #6
bigben2k
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Join Date: May 2002
Location: Texas, U.S.A.
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Quote:
Originally posted by myv65

Another thing that comes into play with submerged pumps like your example is the motor behavior. A split capacitor, single phase, four-pole motor will have a peak efficiency in the range of 65%. The efficiency curve looks like a parabola. So as you move away from the "full rated load", the efficiency will drop off dramatically. A dead head condition will tend to drop the motor output load, but will also bump the motor some along its efficiency curve. I have done absolutely zero work in this area to measure the effects, so I can't say positively how significant this is. All I would point out is that energy input to the motor does not drop as rapidly as the shaft output power drops due to the efficiency curve of the motor.
Now I'm beginning to understand why pump curves aren't straight! Thanks "uncle" Dave!
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