It comes from the formula for capacitance Xc= 1/(2 x pi x freq x C), C in Farads, and the voltage across the capacitor E = I x Xc.
The formula supposedly is good for +- 10%. I used applied voltage while under load and generally it was via a 24 volt transformer. it was good enough for field work. A step up from a continuity tester.
I don’t remember ever mounting one inside a starter. Maybe cause mine were 100hp and below.
You don't need to correct your power factor to 1. The lowest PF that can be allowed before you'll be penalized by the PoCo is 0.85 (at least in my place). That said, target final PF should be greater than 0.85, depending on what capacitor bank is readily available in the market. IMO, a 100 HP motor with a PF of 0.8 needs a 10 kVAr cap bank to be able to bring up the PF above 0.85 PF. There are lots of available worksheets from motor manufacturers for you to use.
They want PF corrected to .95 or better around here, in situations where they require correction anyway. Which for the POCO I tend to deal with the most it is any installation with a 50 HP motor or larger.
Time of year. Peak consumption is summertime for us.
Same here, though sometimes they still running fans in summer, depends when they take the grain to a market. Had years where they are clearing out bins in August because they will be needing storage for the upcoming harvest, and others they are already starting to unload shortly after harvest is done.
POCO here sends out letters in off season to anyone that has too low of a PF. Almost always because of a failed capacitor. Little surprised they don't send them out shortly after discovery. It says on the letter what the penalty is but is a cost per horsepower and not sure if it means per month per season, or just what it actually is. I never have tried to determine if it is worth it for user to keep up the correction or to just pay the penalty. Seem to recall thinking it may be somewhat close to same cost either way though. Just worded in a way to encourage providing the correction.
and I'll bet I can just series a few for 480. Nice find!And providing that PF correction is just as simple as plugging in a bunch of these:
View attachment 2570229
My SIL gave me one for Christmas. She mentioned her husband told her they were a scammy piece of crap, but what could it hurt? I was very polite about it. I said thank you, not mentioning any possible PF savings would be eaten up by energy used in the LED circuit inside. My wife eagerly threw it away when we got home.and I'll bet I can just series a few for 480. Nice find!
and if you believe either statement, well I just don't know.
Correct. It's the POCOs who benefit not the customers -->lower MVAR demand charges from generating plants and lesser system loss! If utilities do not penalize customers with very low PFs, customers won't correct their PFs. Besides, the PFC costs rise exponentially beyond 0.85.
I did a quick calculation and the results tell me that if we compare the costs when correcting up to a PF=0.85 versus the costs incurred correcting up to 0.95, it's about 400% more expensive than targeting a PF=0.85. But those don't matter if you have lots of money to burn!
1fared = 1,000,000 microfarads
But did you factor in any fees charged by POCO for too low of power factor? I didn't give specific penalty for my situation because I don't recall exactly what it was.
Not residential. Not single phase.
Ah yes. Missed something in reading…
