From: ham789@netzero.net   
      
   On 3/20/2013 8:57 PM, 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.   
   >   
   >   
   > Time has passed.   
   >   
   > I installed corrective capacitance based on my spreadsheed and formulas   
   provided by others in the group. Thanks for all the help.   
   >   
   > More Time passed.   
   >   
   > What we learned recently is that though the AVERAGE powerfactor is "low" -   
   .5 or less sometimes,   
   > there are SPECIAL PEAK LOAD EVENTS that may last for a few seconds (less   
   than 5) every minute or two.   
   >   
   >   
   > 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...   
   >   
   > You can guess where this is going.   
   >   
   >   
   > When the load is applied voltage drops from 120 nominal to 106 or so.   
   Solenoids fail to fire. Power factor changes dramatically.   
   >   
   > So, given that my KillaWatt only does averages, we rented a Fluke meter that   
   records mins and maxes within each one-minute interval.   
   >   
   > 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.   
   >   
   > Any other suggested actions?   
   >   
   > 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"   
   >   
   > thanks in advance.   
   > Phil   
      
   Your objective is unclear.   
   When you get the power bill, are you billed for volt-amps or watts?   
   If it ain't broke, don't fix it.   
      
   The KillAwatt is limited to 2kw or so.  Anything that can be measured   
   with that   
   is IRRELEVANT.   
      
   When there's no load, the power factor is IRRELEVANT.   
      
   If you are billed for volt-amps or you just want to be a "good citizen",   
   You want to provide power factor correction at EACH point of load under   
   normal conditions for that load.   
      
   Judging from your statements, your problem is RESISTANCE in the wiring   
   or motors severely overloaded...or both.   
      
   Don't think it makes a lot of sense to try to power correct a transient   
   load at turn-on unless you switch it in ONLY during turn-on.   
      
   A 120V solenoid shouldn't fail to energize at 106V.  I expect  your   
   transient goes much lower than that.   
      
   You need a storage oscilloscope and a current/voltage probe to determine the   
   transient conditions that you experience.   
      
   Think the end result will be bigger wiring.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)