so I'm running my trip like power inverter this morning off the solar power so I'm running my
upright freezer which is out in the garage so in several of my earlier videos have mentioned that
I've done some power factor correction on some of my large AC loads that I run around the house I
specifically did that to make those loads easier to run on this power inverter some of the loads
that I've done that to one is the freezer and then the other one I did was one of my drill presses so
I wanted to show you how I did that how do you decide how to correct the power factor how do
you even measure power factor and what does it do for you okay so here's my DC power meter so
we're doing fifteen point five five volts and thirteen point four three amps 208 Watts that
we're putting into the power inverter so that's power going into the inverter to produce the AC
power so let's swing over and we'll take a look at the AC power that's coming out of the inverter
so this plug comes out of the power inverter and then feeds power into this outlet strip
so we're getting a hundred nineteen point four volts jumping around a little bit and one point
seven two amps so I'm gonna write both of those down and if we drop down 145 Watts I'm gonna also
write that down and here's the volt amps if you take the volts times the amps that's volt am so
I'm putting 204 volt amps into the freezer but that only represents a hundred and forty-four
watts and the reason that's off there is that's your power factor so the power factor says that
only 70 percent of the current that I'm sending to the freezer is useful current so that additional
current that I'm having to supply to the motor that's running the compressor in the freezer is
what's called reactive power so let's take those numbers and we'll punch that into a calculator and
we can see the result of that okay so we have the voltage current and power readings we took
from the freezer compressor motor and it's just a simple matter of plugging those numbers into
this equation and you compute a few intermediate values and it'll tell you what sort of capacitor
you need to correct the power factor so this was the way I learned to do that in school but there
is an easier way and if we slide up here so this power factor calculator is on rapid tables calm
I'll put a link to this in the video description all you need to do is enter the numbers so we had
145 watt so this calculator is in kilowatts here so you got to remember that so it's point one four
five kilowatts and then the amps was one point seven two and we were roughly 120 volts and all
you have to do is hit calculate so I think the kilowatt meter was reading so seven power factor
and if you go down here so here's your correction capacitor so it tells me that I need a 27 micro
farad capacitor so what you want to look for is put your calculated value 27 and then they
most of their listings use UF for micro farad's they don't go by the micro sign it's UF and then
usually if you put in VA C that'll give you an AC pass etre and you want a run capacitor so the two
kinds of passengers you generally find our motor run capacitors and motor start capacitors so a
run capacitor is designed to be energized all the time that the motor is running a start capacitor
is just used for intermittent use on darting a motor so you want to find a run capacitor and so
we could do a search here you know even though I searched for 27 it's showing me a bunch of seven
point five seven point five there's a five so you have to be careful because it may not give
you what you're looking for because 27 is kind of an oddball number so what I did was I searched
for 30 and now there's a whole bunch of 30s come up here's some seven eight dollar ones eight you
know this is probably what you would find at your local HVAC repair shop they'll probably have you
know thing like at Emeco your name-brand you're gonna pay $25 for that capacitor probably really
good but if you go down here you can probably find them for seven eight dollars here's four dollars
51 cents so let's get one of these ordered and we'll go back to the inverter hug the capacitor
into the freezer and see what it does okay so based on that calculator I determined I needed
approximately a 30 micro farad capacitors so this is a 30 micro farad motor run capacitor and then I
just wired up a plug on this that's not the ideal way to do this but just for testing purposes I put
a plug and then I also have I think a 1 mega ohm discharge resistor I'm gonna plug this in
and watch what happens for that and look at that we dropped from one point seven amps roughly down
to one point one eight one point two ounce look down here still about the same power but now look
at the volt amps 142 and if we look at the power factor point ninety seven so that freezer is now
most perfect power factor and let's look at the power inverter in the this is the DC power going
into the power inverter you can see we've charged up a little bit we're now 15 point 6 volts and
right at 12 amps and 188 watts yeah so I've saved over an amp of DC current in about 20 watts of DC
power that I no longer have to put into the inverter because of that capacitor so just
plugging in a little capacitor can save me roughly 10 percent of my power that I need to supply so
if I have my freezer plugged into the grid I don't pay anything for reactive power the way to look at
that is if I have a 15-amp outlet at a hundred and twenty volts I have up to eighteen hundred volt
amps of reactive power that I can have for free I don't have to pay anything for that eighteen
hundred volt amps I only pay for the Watts that I use but power factor is not an issue as long as I
don't exceed the circuit breaker rating I can pull as much as I want but when you take that load and
plug it into a power inverter and you're producing your own electricity that reactive power has
to come from somewhere you know it doesn't just magically appear out of the air you know I've got
to produce it it might not be real power but that current has to come from someplace so this doesn't
show up all that big a number in the half to one amp range but let me see if I can set up my drill
press and we can take a look at that okay now I've got my drill press running so it's running
no load I've just got the Chuck spinning and let's see we're pulling eighteen point two amps and 288
watts okay here's the kilowatt meter 119 volts and still the same let's look at that four point
three four camps 163 watts there see we're putting 517 volt amps and power factor is point three one
the drill press has a pretty big motor but it's running at no load right now it's using roughly
half of the current output of the power inverter it's a thousand watt 120 volt inverter so that's
roughly eight amps of output I'm using half of the current output just to keep that motor spinning
okay let's go back to the power factor calculator and look at the drill press motor so when we were
testing the freezer that motor was under load because the motor and the compressor are in a
sealed unit and there's no way to run the motor without running the compressor the drill press on
the other hand is just spinning the chuck in the air there's no load on it so you don't need to do
this power factor measurement at any specific load you just need a consistent load so for the drill
press we had point 1 6 2 kilowatts again and 4.34 amps and if you want to you can change the voltage
they just have 120 as the hard coded value and calculate and there's the point 3 1 power factor
that we measured and this is telling me I need a 91 point 8 micro farad capacitor now if we
go over here to ebay 90 micro farad capacitors are available here's one for $35 here's 17 50
there's a $45 one but yeah you can get these but 90 is kind of an oddball number kind of like the
27 so in this case I found 80 it was a little more common size for a run capacitor and here 659 1112
$16 641 right there this is even a dual capacitor you've got an eighty and a 5 micro farad so let's
get one of these ordered up and we'll go plug it in to the drill press we'll hook up my run
capacitor and see what that looks like okay so I've hooked up my capacitor according to the
calculator I needed approximately 80 micro farad's because this was a larger load and it had a worse
power factor you saw it was 0.3 one I think it was so now instead of four point three amps
we're now pulling one point three amps 145 watt it was 162 before so we've actually reduced the
resistive losses we're not having to pump three amps of current back and forth out to the garage
to power that drill press and there's the Volt amps 165 and let's look at the power factor so
we got pretty close point eight seven point eight six let's go look at the DC power okay so here's
the DC power net so we can save roughly twelve point seven five amps and about two hundred watts
I was using 18 amps and 288 watts so I've saved 88 watts of power and about five amps of DC current
by not having to supply those extra three amps of reactive power so you can see that the worse your
load power factor is the more actual DC power you will save by plugging in a correction capacitor so
I'll show you how the drill press is hooked up here yeah so there's my drill press right there
and all I did - why you're in the capacitor was I took off this switch panel here so the
capacitor is basically just wired across the motor terminals permanently but it's behind the switch
so if I turn the switch off everything's off if I turn it on everything's hooked up one thing I
do notice with this drill press is it seems less likely to stall out while you're drilling than it
did before it just seems to run smoother and now the capacitor is basically supplying three amps
of current for free all the current that comes in the power line is available to use for torque
versus before three of those amps got skimmed off the top so it's kind of like you've just bolted
on a little turbocharger on the side so yeah I find that the drill actually works better with
that capacitor attached than without the capacitor just to wrap up here this is the capacitor I have
running into the freezer so I built this little transfer switch so the idea is I can plug this
into my power inverter and then I also have grid power plugged in on the top side there and so the
freezer is plugged into that plug and then I plug the capacitor in up on top the only problem with
this setup is that capacitor is plugged in all the time so when the freezer is on it's doing its job
but the problem is when the freezer turns off that capacitor is still connected across the incoming
voltage so what I really need to do is I've got to pull the freezer here away from the wall so I
can get to the back side and then I need to get that capacitor wired in behind the thermostat
switch so that the capacitor turns on and off when the freezer compressor turns on and off but
anyway hopefully that will help clear power factor and it's pretty easy to correct measure a couple
of numbers put them in the calculator find a capacitor of approximately the right size and then
figure out how to hook it up that will probably be the hardest part is figuring out how to get the
capacitor permanently wired in to whatever device you have that's the only really creative part of
the process everything else is just measure some numbers plug them into a calculator you
get a result and then just make sure you get a high enough voltage rating and get a motor run
capacitor or not a motor start capacitor and you should be set if you have any questions
about that post up in the comment section down below and as always thanks for watching