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PF is no ta huge problem for TSW inverters, but can be a major problem for MSW inverters. However even TSW inverters can have a problem for example running a lot on non linear loads like switching power supplies found in Desktop computers and cheap CFL light bulbs where PF can be .6 or even less. Most TSW inverters can only handle .8 PF at full power. -
Originally posted by russ View PostFor residential grid connect PF is a problem for the utility - not the homeowner.
While a residential connection does not usually have a PF penalty added to their bill by the Utility, a low PF means they have losses in their electrical system. These losses will use up some of the total available kva of their transformer capacity in their inverter.Leave a comment:
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Originally posted by Sunny Solar View PostPower factor (PF) is one of those measurements that have no effect on 99.9% of people. Most people buy a AC or refrigerator or microwave oven without ever needing to know their PF.
Grid power can cope with just about every residence having some devices with far from perfect PF.
Its only a concern to the following electrical engineers designing big industrial factories and similar, power companies charging those factories,and when you are into using off grid solar power for your residence.
To most of the people that need to get PF as close to 1 as possible are off grid solar power users. The reasons being that "bad" PF wastes your battery/ies power. Less run time from any given battery capacity.
If the old standard of assuming PF of .8 then you wont go far wrong in estimating your battery power usage.
PF is really one of those measurements like Lumens ..If your room is not bright enough you dont go checking the Lumens ,you just go upgrade your existing 60w lamp for a 100w one...You get the idea.Leave a comment:
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Power factor (PF) is one of those measurements that have no effect on 99.9% of people. Most people buy a AC or refrigerator or microwave oven without ever needing to know their PF.
Grid power can cope with just about every residence having some devices with far from perfect PF.
Its only a concern to the following electrical engineers designing big industrial factories and similar, power companies charging those factories,and when you are into using off grid solar power for your residence.
To most of the people that need to get PF as close to 1 as possible are off grid solar power users. The reasons being that "bad" PF wastes your battery/ies power. Less run time from any given battery capacity.
If the old standard of assuming PF of .8 then you wont go far wrong in estimating your battery power usage.
PF is really one of those measurements like Lumens ..If your room is not bright enough you dont go checking the Lumens ,you just go upgrade your existing 60w lamp for a 100w one...You get the idea.Leave a comment:
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Originally posted by Beanyboy57 View PostIs knowing PF critical for me at this point or useful for me to understand?
The two areas that you might look into if you want to learn more about power factor are peak rectification and complex impedance. Peak rectification refers to devices that only take power during a small part of the AC waverorm (requiring an inverter that provides a higher peak power) and complex impedance describes loads whose current waveform is not completely in sync with the voltage waveform. Both are more difficult for an inverter to drive, but modern inverters are designed with non-ideal loads in mind.Leave a comment:
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PF
Originally posted by Sunking View PostI am OK with that, but before you started educating yourself did you have any clue what PF is? Could you define it and how to calculate it.
OK since you have some knowledge can you define and know how to calculate it now?
As I said I am a new to this and perhaps I will take some time to get to an intermediate level of knowledge which will probably be where I peak in this particular field of study. I know my own capabilities and where my strengths lay.
My main hobbies are gardening and racing Go-karts, perhaps I know enough about them to teach some of you electrical guys a thing or two!!
Is knowing PF critical for me at this point or useful for me to understand?Leave a comment:
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Originally posted by Beanyboy57 View PostI have to disagree with you SK,
OK since you have some knowledge can you define and know how to calculate it now?Leave a comment:
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Cheers!!
Originally posted by Sunking View PostI chuckled when I first read this post. This is pretty much a DIY forum and the posters looking for help have ZERO electrical knowledge and all this is is GREEK to them and will never understand one bit of it.Leave a comment:
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Originally posted by randl View PostMy bad, inetdog and Sunking, sorry.Leave a comment:
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My bad, inetdog and Sunking, sorry. I knew it didn't feel right dividing by 0.8. The "standard" correction should be VA * 0.8.
randlLeave a comment:
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Originally posted by inetdog View PostI have always thought that for a given load the VA number was greater than to equal to watts, not the other way around?
Watts = VA * PF
VA = Watts / PF.
PF = Watts / VA
PF is a number of 1 or less where 1 is a purely resistive load.Leave a comment:
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Originally posted by randl View PostYou could measure the actual power use of each load. If you're calculating a hypothetical load, my electrical engineer friend and my quick read on this topic both tell me that accepted practice is to divide VA by 0.8. If VA=1000 then you would correct to 1249 Watts. This estimate is apparently well accepted but, of course, it could be low for a purely reactive load.Leave a comment:
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Originally posted by martin1025how can we calculate this and any proper to change ............Leave a comment:
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There's a good, concise explanation of power factor in the August/September 2012 edition of Home Power magazine. It discusses resistive vs. reactive loads, shows an example of in phase and out-of-phase reactive load plots, mentions what sort of loads will have high power factors, etc.
The trig explanation isn't too helpful for those who don't see the plots...Leave a comment:
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Originally posted by Sunking View PostI chuckled when I first read this post. This is pretty much a DIY forum and the posters looking for help have ZERO electrical knowledge and all this is is GREEK to them and will never understand one bit of it.
asking questions about power factor (why does my 1/2 hp motor draw 1,000 watts) and they figure it out, our work here is done.Leave a comment:
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