[RE-wrenches] Power Factor

[R. Walters]

Power factor expresses the time difference  between voltage peak and  
current peak on each of their sine waves. If both current and voltage  
waves are "in time", (their wave peaks match up) power factor is 1.  
If one is ahead or behind the other, it's not. Think about an  
electric motor: we hit it with a voltage wave, and a fraction of a  
second later, it actually moves, and the current wave happens. There  
is a little lag there. Resistive loads like lights have very little  
lag, and big electric motors coming up to speed can have horrible PF.
There is much more to it, with reactance, "real" and "imaginary"  
numbers?!, etc. but basically, we wrenches need to know that  
everybody wants  Power factor to be close to 1.
Obviously there isn't PF on DC, and it is my understanding that most  
inverters can operate at most power factors.
Not 100% sure, but I think GT inverters would help not hurt the PF  
problem in most situations.

Correct me on any and all of this, Oh fellow wrenches,

R. Walters
Solarray.com
NABCEP # 04170442	



On Jul 30, 2009, at 9:19 AM, boB Gudgel wrote:

> Ron Young wrote:
>> Ok, so all seem to be in agreement more or less. How do I break it  
>> to British Columbia Hydro? :-|
>>
>> I think they must be misunderstanding what they are asking for but  
>> the question is in the section for PV and on the same line as the  
>> total output in Kwh of the PV. Power Factor %
>
> It was most likely just  a trick question.
>
> You're gonna fool them, though !   :)
>
>
> boB
>
>
>
>>
>> I'll contact them and see where this goes but I don't fully  
>> understand what power factor is which will make it hard to argue  
>> my case. My understanding is that it is the difference between  
>> what the utility supplies to a residence vs. the actual loads  
>> being used by that residence expressed as a percentage.
>> I came across the following course offering by SEI that discusses  
>> Power Factor with reference to PV:
>>
>> POWER FACTOR AS IT RELATES TO SOLAR INSTALLATIONS Presented By:  
>> Michael Smith of Alpine Management Systems
>>
>> This session will deal with power factor: What is power factor?   
>> What causes low power factor?  Why improve your power factor? This  
>> session will explain the role of power factor correction as it  
>> applies to solar installations. There are currently over 67,000  
>> KVAR installations in 26 countries resulting in phenomenal energy  
>> savings with a corresponding reduction in greenhouse gas  
>> emissions. Session includes several KVAR installations and the  
>> resultant savings. http://www.solarenergy.org/workshops/docs/ 
>> industry08_trainingdetails.pdf
>>
>> Ron
>>
>> On 30-Jul-09, at 7:43 AM, Wind-sun.com wrote:
>>
>>> There is no such thing as a power factor for DC or for panels.
>>>  ................................................................... 
>>> ...............................
>>> Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
>>> Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
>>> .................................................................... 
>>> ..............................
>>>
>>>     ----- Original Message -----
>>>     *From:* Ron Young <mailto:solareagle at solareagle.com>
>>>     *To:* RE-wrenches <mailto:re-wrenches at lists.re-wrenches.org>
>>>     *Sent:* Wednesday, July 29, 2009 5:45 PM
>>>     *Subject:* [RE-wrenches] Power Factor
>>>
>>>     Can anyone point me in the direction to find the power factor  
>>> for
>>>     Sanyo HIT N 205 panels? The utility is requesting it on a net
>>>     metering interconnection application.
>>>     Ron Young
>>>     earthRight Products - Solareagle.com
>>>
>>>
>>>      
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