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   alt.energy.homepower      Electrical part of living of the grid      2,576 messages   

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   Message 1,626 of 2,576   
   philkryder@gmail.com to philkryder at gmail   
   Re: power factor - round 2   
   21 Mar 13 17:22:57   
   
   On Wednesday, March 20, 2013 8:57:05 PM UTC-7, philkryder at gmail wrote:   
   > A couple years back some folks in this group helped me to use a KillaWatt    
   device to deterimine powerfactor on some "lighly loaded" ac motors.   
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   > Time has passed.   
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   > I installed corrective capacitance based on my spreadsheed and formulas   
   provided by others in the group. Thanks for all the help.   
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   > More Time passed.   
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   > What we learned recently is that though the AVERAGE powerfactor is "low" -   
   .5 or less sometimes,   
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   > there are SPECIAL PEAK LOAD EVENTS that may last for a few seconds (less   
   than 5) every minute or two.   
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   > Coincident with those peak load events, control circuits in the same   
   "neighborhood" - i.e. cicuit need to fire control solenoids for hydraulic   
   controls. The motor is a half-horse 120v 60 cycle that drives a hydraulic   
   pump. On average - 95% of the time -   
    there is no load - but, when there is a a solenoid opens a valve to a   
   hydralic motor and then, other solenoids open valves to hydraulic cylinders...   
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   > You can guess where this is going.   
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   > When the load is applied voltage drops from 120 nominal to 106 or so.   
   Solenoids fail to fire. Power factor changes dramatically.   
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   > So, given that my KillaWatt only does averages, we rented a Fluke meter that   
   records mins and maxes within each one-minute interval.   
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   > I'm inclined to re-tune the capacitors based on highest power Factor  seen   
   over an entire 10 hour shift, rather than the average seen by the Killawatt   
   while I happen to be looking.   
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   > Any other suggested actions?   
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   > Also, "what happens" with a corrected circuit at a 98% power factor when the   
   load increases and the motor's power factor rises from .5 to .85 causing the   
   circuit to be "over corrected"   
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   > thanks in advance.   
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   > Phil   
      
      
   more background data.   
      
   we are off grid.   
      
   We're not trying to save money.   
   We're trying to run more reliably.   
      
   Our initial problem was popped breakers due to the high current flow due to   
   the imaginary current.   
      
   thus the power factor correction.   
      
   step 1 was to remove the caps. - done.   
      
   I still have the question "what happens when the caps are in place and the   
   motor's power factor improves to .85 from the average .5?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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