Originally posted by randl
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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.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?MSEE, PEComment
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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?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.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.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.[SIGPIC][/SIGPIC]Comment
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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.Comment
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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.MSEE, PEComment
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Originally posted by Sunking View PostPF 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.
You are also correct about the non linear switching loads. They cause harmonics which increases both Voltage and Current distortion which can cause bigger losses than a low PF.
Actually that is my job to help our customers eliminate these harmonics by installing HMI type transformers. By putting in transformers with higher efficiencies that also mitigates the triplet harmonics there is a good change of reducing their electric bills by 4 to 6% as well as eliminate issues caused by the harmonics.Comment
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Originally posted by SunEagle View PostA bad or low Power Factor is no good for either the utility or the homeowner. Utilities charge a PF penalty to customers to help them reduce waste on their distribution system.
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.
For commercial use it is standard to have a penalty clearly charged.[SIGPIC][/SIGPIC]Comment
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Originally posted by russ View PostPlaying with words? Where on the residential bill does it specify a penalty for poor power factor? What utility anywhere around points out a charge to the residential customer a penalty for poor power factor? None that I know of. Of course the end customer always pays.
For commercial use it is standard to have a penalty clearly charged.
A commercial meter can be configured to record either average or worst case PF in addition to recording the real power (watts) consumed.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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Originally posted by russ View PostPlaying with words? Where on the residential bill does it specify a penalty for poor power factor? What utility anywhere around points out a charge to the residential customer a penalty for poor power factor? None that I know of. Of course the end customer always pays.
For commercial use it is standard to have a penalty clearly charged.
You are also correct when you say the customer always pays one way or the other. Utilities will find a way to pass on the costs to all customers.Comment
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Originally posted by inetdog View PostThe only way a residential customer would end up paying more for a high PF is if the utility-supplied meter reads incorrectly in the presence of higher harmonics in the current waveform. And as far as I know, none do, but I am open to a counterexample.
A commercial meter can be configured to record either average or worst case PF in addition to recording the real power (watts) consumed.[SIGPIC][/SIGPIC]Comment
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Originally posted by russ View PostNot really true - the costs, including losses due to poor power factor, are paid by the customer - it is just averaged out and tacked on to all bills. In the event all power factors were 1 the utility costs would be less.
BTW, since the problems an inverter has with low PF loads are most noticeable near full rated output, the thing you have to watch is the PF of your largest (usually motor) loads. If the only thing you are powering is CFLs and computer power supplies, you are probably nowhere near the full output of your inverter unless that is the entire load that you have planned for.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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