[RE-wrenches] Power Factor
Matt
solarone at charter.net
Thu Jul 30 17:28:56 PDT 2009
Hi Jay,
I think I'll check his wire connections at all the connection points first, and then the next time I'm in the area, bring my Fluke (which DOESN'T measure PF) for a closer look. Believe it or not, his meter is one of those mini GB thingies, analog of course, that would be better as a paper weight. The whole problem is really a hard thing to ferret out with face flies buzzing around your ears and eyes. :-(
Matt
---- jay peltz <jay at asis.com> wrote:
> Hi Matt,
>
> I would try a few things, but its very curious to me that the inverter
> won't even get a try out of the motor.
> I've seen plenty of motors not work, but they tried to start.
>
> And given the 7k genny starts it, the 4k inverter should start it too.
> I would check the current under load and surge if possible.
> Check the battery voltage.
> Could be a bad cap on the motor too.
>
> I've got a new meter that measures PF on the way, just for problems
> like this.
>
> jay
>
> peltz power
>
>
>
> On Jul 30, 2009, at 4:03 PM, Matt wrote:
>
> > Unh - hunh, but it will run on the generator. If it didn't, I would
> > go for the bad starter or motor, but it "seems" like the PF could be
> > an issue??
> >
> > Matt T
> > ---- boB Gudgel <boB at midnitesolar.com> wrote:
> >> Matt wrote:
> >>> Possibly a PF question, or maybe one for Magnum - boB,
> >>>
> >>> One of the guys at work is (almost) running a 3/4 hp sub pump with
> >>> a Magna AE 48. Or rather, he isn't. According to him when he first
> >>> fired it up, it operated the pump just fine. The next time he
> >>> tried, though. he couldn't even get a buzz out of the starter. No
> >>> workee.
> >>>
> >> Sounds kind of like a "pump is broken or worn out" problem, doesn't
> >> it ?
> >>
> >> If there is enough ac voltage applied to the pump, the it should do
> >> ~something~, or lights should dim or some
> >> kind of sign should show itself, wouldn't you think ? Otherwise, I
> >> would suspect it might be a surge problem.
> >>
> >> Is there a pilot light or something ? Maybe a fuse blew or breaker
> >> tripped somewhere ? (when the pump went off?)
> >>
> >> Doesn't sound like a PF problem though... However, since you mention
> >> it, with loads that are not a 1.0 power factor,
> >> at least for displacement power factor, when reactive phase shift is
> >> involved, the inverter must be able to "sink" current
> >> from the stored reactive energy as well as be a source to the motor.
> >> The Magnum does that just fine, as does any other
> >> decent inverter.
> >>
> >> Maybe Tony, Eldon or Gary at Magnum has seen this before ?
> >> 425-353-8833
> >>
> >> boB
> >>
> >>
> >>
> >>
> >>
> >>
> >>> The inverter runs all the other loads in the house fine, just not
> >>> the pump. He can run the pump directly from a 7 kW generator with
> >>> no issues.
> >>> So, do you think we're looking at a power factor deficit,(I think
> >>> not), a motor starter problem or an inverter issue? I have to
> >>> admit to being somewhat baffled by this one because it ran the
> >>> pump once, but not after.
> >>>
> >>> Matt T
> >>>
> >>>
> >>> ---- boB Gudgel <boB at midnitesolar.com> wrote:
> >>>
> >>>> boB Gudgel wrote:
> >>>>
> >>>>>> So, because of the different ways of specifying PF, it is
> >>>>>> always best
> >>>> to think of Power Factor as being the ratio of real (in phase)
> >>>> power, or
> >>>> VA to reactive power >>(VARS or "Volt Ampere Reactive"). That
> >>>> will
> >>>> work in all cases.
> >>>>
> >>>>
> >>>> OOOps ! See, this can get confusing. Reverse what I just
> >>>> said Power
> >>>> Factor... " Definition: The ratio of true power to apparent
> >>>> power" as
> >>>> David Brearley had just posted. Otherwise, that calculation can
> >>>> give
> >>>> you an answer that is GREATER than 1.0 and you don't want that !
> >>>>
> >>>> Had to eat some of my words. I just wanted to point out that the
> >>>> phase
> >>>> shift method was called DPF. Didn't Ian Woodenden do an article
> >>>> on PF
> >>>> recently too ? If not, he or someone probably should in one of
> >>>> the two
> >>>> HP magazines.
> >>>>
> >>>> boB
> >>>>
> >>>>
> >>>>> R. Walters wrote:
> >>>>>
> >>>>>> 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.
> >>>>>>
> >>>>> This definition of power factor only applies for linear loads with
> >>>>> only inductance or capacitance (with resistance) and is called
> >>>>> "Displacement Power Factor (DPF) and you will see that on some
> >>>>> power
> >>>>> meters.
> >>>>>
> >>>>> For non-linear loads, like battery chargers or computer power
> >>>>> supplies
> >>>>> without PF Correction, the current waveform (on an O-scope) looks
> >>>>> nothing like a sine or cosine wave. The current "spikes up" at
> >>>>> the
> >>>>> AC voltage peaks. It actually *looks like* it might be in
> >>>>> phase, BUT
> >>>>> the current and the voltage do NOT look the same. It's non-
> >>>>> linear.
> >>>>> Lower than 1.0 power factor for sure.
> >>>>>
> >>>>> For a grid tie inverter, resistive heater or any load that has a
> >>>>> PF of
> >>>>> 1.0, the current and voltage waveform will both look exactly
> >>>>> the same
> >>>>> AND there will be no phase shift. They are both linear and all
> >>>>> current and voltage is in phase at every point in the AC cycle.
> >>>>>
> >>>>> So, because of the different ways of specifying PF, it is always
> >>>>> best
> >>>>> to think of Power Factor as being the ratio of real (in phase)
> >>>>> power,
> >>>>> or VA to reactive power (VARS or "Volt Ampere Reactive"). That
> >>>>> will
> >>>>> work in all cases. (Real Vs. Apparent power is the same thing).
> >>>>> Apparent power is what you get when you multiply
> >>>>> your RMS meter's Voltage by the RMS current and is called VA Volt
> >>>>> Amperes) V x A will be the highest measured number, that is
> >>>>> unless
> >>>>> the PF = 1.0 in which
> >>>>> case both will measure the same.
> >>>>>
> >>>>> Some of that measured VA, or apparent power will be "in phase"
> >>>>> and is
> >>>>> the "real" or "true" power. Some of that VA may be reactive,
> >>>>> (inductive or capacitive that is) and is the "out of phase"
> >>>>> portion.
> >>>>> Capacitive and inductive reactance is ALWAYS 90 degrees out of
> >>>>> phase
> >>>>> in current and voltage.... It's just a matter of how MUCH of your
> >>>>> power is 0 degrees phase shift and how MUCH of that VA is + or
> >>>>> - 90
> >>>>> degrees out of phase. If ALL of the current is in phase with the
> >>>>> voltage, then
> >>>>> the power factor is 1.0. That is, if you lay them on top of each
> >>>>> other, they will look the same on an oscilloscope if power
> >>>>> factor = 1.0
> >>>>>
> >>>>> It can get way more complicated that this too, but that's
> >>>>> basically
> >>>>> it. Feel free to add to this.
> >>>>>
> >>>>> boB
> >>>>>
> >>>>>
> >>>>>
> >>>>> power meters.
> >>>>>
> >>>>>
> >>>>>
> >>>>>> 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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> >>>>>>>>>
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