Question on inverters
rich
engineering? I know their good, but in a crisis, these companies will cease
to exist. We are survivalists and as such we should understand how to
design build or fix them. The parts should be radio shack accessible and
someone here must be an electronics engineer. How about a book or set of
plans or homemade designs? Let's hear from someone who knows something. I
think we need to get serious again on self sufficiency.
Gene
Get some good old ham-radio manuals. They cover home-brewing most of these
things, from inverters to radios that you can tune in whatever shortwave
stations are still up and broadcasting.
Lawrence Glickman
Self-sufficiency is mostly a HOAX anyhow.
Here.
REMOVE AND THROW AWAY everything around you that you personally did
not create or make.
Now, what do you have.
Like I thought. NOTHING.
Nuf said,
Lg
Lou Boyd
I'm an electrical engineer and do know how to design, build, and
maintain power inverters. I also recognize the amount of effort required
for a reliable and efficient design. The basic concepts are fairly
simple, but the engineering details in a "bulletproof" design are not
simple. I agree that its good to understand them enough to properly
maintain them, but don't expect to get the parts for a reliable high
power inverter from Radio Shack. You are no more self sufficient if
you buy the parts from Radio Shack than buying them from Trace or
Reliance. If you build your own I can guarantee you that you will
either have a less reliable unit or it will cost many times more than
one which has had the engineering costs spread over hundreds or
thousands of units. I have a 8kw Reliance, a 1.5kw Emerson, and 2.4kw
and 18kw Best UPS's. No way could you make any of those or even
maintain them with parts from Radio Shack. These quality commercial
units have all given trouble free service for the four to 15 years I've
been running them.
--
Lou Boyd
Fairborn Observatory
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 80,000 Newsgroups - 16 Different Servers! =-----
Matthew Henry
power amplifier, and take the output and run it through a transformer. Run the
amplifier off of your battery and you have a home brew inverter. Just don't use
it on anything that is picky about voltage and frequency stability
, and don't expect high efficiency.
rich
further and share what I find with the group. I agree homemade might not be
anywhere near as good as trace but any skill learned in life could mean life
and death. I remember a story of a small boy slated for death in a
concentration camp. He overheard some soldiers talking about how to get
somewhere. By providence he not only knew but spoke that particular
language, so they spared his life. Yes I know he helped the enemy and may
have doomed others, but knowing the nazis they would have gotten there
anyway. A little knowledge saved his life.
"rich" <rpa...@ccsinc.com> wrote in message
news:9437d5$amj$1...@dfw-ixnews3.ix.netcom.com...
Lou Boyd
inverter???
--
Lou Boyd
--
Mark Robertson
"Lawrence Glickman" <lgli...@ameritech.net> wrote in message
news:109a6tomqkomheb4k...@4ax.com...
Woah. Just because I aquired items from an pre-existing technological base,
does not mean I can not become self sufficient of that base using these
items. As long as I am capable of repairing and maintaining said items.
Storing parts and tools and learning the neccessary skills is all part of
this. Bootstrapping from point zero is pointless and extremely time
consuming. The question is, if I loose my support base, am I prepared to
achieve a standard of living that I find satisfactory. If not I am gambling
on not loosing that support base. Some of us prefer not to gamble.
Preparation can be expensive. Getting caught unprepared can be deadly.
Lawrence Glickman
And I agree with every word you just said Mark. Every word. So maybe
what I'm looking for is Self-Reliance, rather than self-sufficiency.
When Thoreau went to Walden Pond, he set up shop in his friends
hunting cabin, IIRC. From there on out, I don't know -how- he
acquired his food, re-supplied himself with clothing, and so forth.
The only point I wish to make is that the only really self-sufficient
are various tribes around the world, like the Inuit, Yanomama, and
Fiji Island, / New Zealand Indians, and so forth.
Us English Settlers ( Mennonites excepted ) have formed a loose
alliance with one-another to trade service and goods. But who amongs
us whities can clothe, feed, shelter him/herself FROM SCRATCH. ???
Not too many people I know; not even the gung-ho GI Joes.
The People of the Jungle know how to do this. They started learning
when they were babies and have studied it all their lives (
self-sufficiency ) but I -expect- if you took one of our group members
and de-nuded him/her of _everything_, including the clothes on their
backs, that didn't come from their own sweat and labor, they would
perish in the wilderness overnight.
So what YOU and I are really talking about is STOCKPILING, which in my
opinion is NOT exactly the same thing as self-sufficiency. According
to my way of thinking. Because we are just consuming stuff that was
produced by others, not ourselves.
Self Reliance, OK. Self-sufficiency according to my definition is
something else, and I don't mean to be nitpicking, but rather wish to
make a point. It is EASY to stockpile. Quite another thing to go it
alone in the wild. Few among us would survive it for long. I am sure
of that.
Lg
Aaron R. Kulkis
>
> Buying a high power car stereo is more "self sufficient" than buying an
> inverter???
HaAHAHAHAHAHHA
--
Aaron R. Kulkis
Unix Systems Engineer
DNRC Minister of all I survey
ICQ # 3056642
H: "Having found not one single carbon monoxide leak on the entire
premises, it is my belief, and Willard concurs, that the reason
you folks feel listless and disoriented is simply because
you are lazy, stupid people"
I: Loren Petrich's 2-week stubborn refusal to respond to the
challenge to describe even one philosophical difference
between himself and the communists demonstrates that, in fact,
Loren Petrich is a COMMUNIST ***hole
J: Other knee_jerk reactionaries: billh, david casey, redc1c4,
The retarded sisters: Raunchy (rauni) and Anencephielle (Enielle),
also known as old hags who've hit the wall....
A: The wise man is mocked by fools.
B: Jet Silverman plays the fool and spews out nonsense as a
method of sidetracking discussions which are headed in a
direction that she doesn't like.
C: Jet Silverman claims to have killfiled me.
D: Jet Silverman now follows me from newgroup to newsgroup
...despite (C) above.
E: Jet is not worthy of the time to compose a response until
her behavior improves.
F: Unit_4's "Kook hunt" reminds me of "Jimmy Baker's" harangues against
adultery while concurrently committing adultery with Tammy Hahn.
G: Knackos...you're a retard.
dig...@jps.net
A voltage inverter does three things. It takes direct-current and
changes it to alternating current and steps up the voltage and
current. The curcuitry invovled is relatively simple and yes Radio
Shack has most of the parts needed. There are a couple of different
ways to build an inverter depending on how much wattage you want it to
handle. A stepping transformer is the best method in my opinion.
Basically you make a rectifying circuit to change say 12 volts DC to
12 volts AC, you then need a stepping transformer to punch the voltage
to 120. You would then need a circuit to amplify the current (amps) to
a sufficient amount which is done with a series of transistors. A
voltage inverter is a project that a lot of beginning electronics
techs do as a teaching project. A really well made stepping
transformer would be the most expensive part of the whole thing.
KB9WFK
<dig...@jps.net> wrote in message
news:vkuu7tcdthg6becuh...@4ax.com...
I don't believe it possible to step up the voltage AND the current. (That
would be a better than perfect system as it would have negative losses.)
Voltage, no problem, but where is the "series of transistors" getting this
extra current it is imparting on the circuit? Lead acid batteries are
capable of very high current output and would have no need of being
amplified any way.
I'm pretty sure I'm right on this but others feel free (like this needs to
be said hehe) to correct me here.
Maybe you meant something else?
Harmless Fuzzy Bunny
"KB9WFK" <KB9...@mindspring.com> wrote in message
news:95o6jc$fok$1...@slb0.atl.mindspring.net...
You're correct. The best way of looking at inverters is as _power_
converters. A perfect unit would take in, say 1200 watts DC
(12V at 100 Amps) and put out 1200 watts of AC (120V at 10 Amps)
so yes, current is reduced.
While basic, low-efficiency inverters are trivial to make, there's a
reason why Trace gets so much money -- there's some serious
engineering involved in getting products with 90-95% conversion
efficiency. Like a lot of situations, there's a free market force
at work here: which is more cost effective -- more generating
capacity and a low-efficientcy inverter, or less generating
capacity and a high-efficiency inverter? In the case of solar
power systems, generating capacity is expensive, at about
$4/watt or so. The big Trace SW4024 might set you back $2,500,
but it's 94% efficient so I only waste 60 watts of my 1KW panel
system. For the same amount of power output, I could use a
50% efficient inverter, but I'd need to double my panels --
at a cost of $4,000!
So the Trace is a bargain. If you've got generating capacity
that's really cheap (like hydro, for example) then maybe a
cheap inverter is an OK deal.
As far as dealing with a crisis -- blow off the inverter and go
DC. My setup uses DC for critical things like water pumping,
and AC for the fluffy things like running appliances.
Speaker to Animals
>
A high powered inverter is no toy.
I have a 2.6KVA homebuilt inverter that can use 12/24/48V DC.
At the higher input voltages it can generate additional power.
It and hte dirver (a quasi sinewave) are derived from Tab Books No1128, How to
Make Home Electricity From Wind, Water and Sunshine.
I have about $200.00 in parts, and I have an extremely well stocked "junk"
box.
At the rated output, from 12V, it draws around 26Amps. [at 24V=13A, 48V=7A]
It is LARGE and generates considerable heat. And it has a very anoying BUZZ.
And wipes out any really weak RF signals.
And to use it effectivly we have had to adopt some exotic load managament.
I use a CMOS Z80 to monitor which appliences need power, never allowing two
heavy devices to start at the same time. And I had to build a power factopr
corrector. {which is why inverters and smaller generators are speced in KVA
instead of Watts..and this is a fun topic that we could spend months on, lets
just say that that 1 HP drill press will use 3 or 4 times the energy it needs
due to "Power Factor". Switch mode power supplies, like in you PC, ,onitor
etc, are even worse} Your Home, Shop, Business is a system. And you have to
tackle the energy needs from a system view point. Home made power will always
cost more than power from a "grid". But, if you are out in the boonnies, are
desire independence, it is either make your own, or do without.
We are switching to 12V DC for as many "devices" as we can. Replacing
incandescent with florescent or LED. Giving up the waffle iron. Debating on
just how much we need a PC. Yea they are handy, but like that drill press they
suck energy. Even this little POS laptop draws 12V at 1.3 amps. The Inkjet
printer draws 80 Watts from the 120V AC. Going off the grid will require a
whole life styple change. No leaving room lights on when you leave. No big
ouside security lights. No big screen TV. IS it for everyone?
Not really. Most people can not balance their checkbook, much less understand
their power budget.
Don Kulha
Speaker to Animals wrote:
> But, if you are out in the boonnies, are
> desire independence, it is either make your own, or do without.
> We are switching to 12V DC for as many "devices" as we can. Replacing
> incandescent with florescent or LED. Giving up the waffle iron. Debating on
> just how much we need a PC. Yea they are handy, but like that drill press they
> suck energy. Even this little POS laptop draws 12V at 1.3 amps. The Inkjet
> printer draws 80 Watts from the 120V AC. Going off the grid will require a
> whole life styple change. No leaving room lights on when you leave. No big
> ouside security lights. No big screen TV. IS it for everyone?
> Not really. Most people can not balance their checkbook, much less understand
> their power budget.
Trust a Kzin to cut to the heart of the matter :o)
Energy management is the key to energy independance. If you visit our website in
the downloads section you'll find an article called LOADCALC.PDF which will shed
a lot of light on the issue. I switch on my inverters for AC power to run the
TV/VCR, run the coffee grinder, charge the notebook, run the bright lights
(Sylvania-Osram compact fluorescent) etc. My ham radios, broadcast radio, LED
lights, charger for nicads, my scanner, water pump, fans, are all DC. I've gotta
make a DC charge cord for my Toshiba....
What type of inkjet burns 80 watts Speaker?, Sheesh, must be an e-size plotter. I
haven't tested my Epson 740 but my HP 660 used to use about 15 watts printing
(measured). I'll look over the specs on the Epson.
Lou Boyd
>
> On 8 Feb 2001 02:00:59 GMT, Dante'@inferno.net (Speaker to Animals)
> wrote:
>
> >which is why inverters and smaller generators are speced in KVA
> >instead of Watts..and this is a fun topic that we could spend months on,
>
Kilo Volt Ampere.
With alternating current the voltage an current waveforms do not have to
be of the same phase. If the they are in phase then volts times amps =
watts. But only the portion of the voltage mulitplied by the componeent
of the current which is in the same phase as the voltage delivers
energy. The meter on your house measures the rate of energy flow. It's
a wattmeter. If you drive an inductive or capacitive load the current
and voltage may be high while the energy delivered is low. Therefore
inverters and some other equipment is rated by the voltage and current
multiplied together without respect to the phase. Heating of the
internal components of an inverter is generally independent of the phase
of the load and is the limiting factor. In an AC system elivered energy
in kilowatts can never exceed the KVA value, but it can be less. In a
DC circuit KVA and kilowatts are the same.
Hopefully this thread won't last months...
Mike Burns
pepto...@lycosmail.com wrote:
> On 8 Feb 2001 02:00:59 GMT, Dante'@inferno.net (Speaker to Animals)
> wrote:
>
> >which is why inverters and smaller generators are speced in KVA
> >instead of Watts..and this is a fun topic that we could spend months on,
>
> Without spending months on it, can you explain what is a KVA?
>
> Thanks.
KVA's are kilo-volts-amps, which means KVA=V*A/1000. It's a lot like
kilowatts, except that it's possible to make a device (such as a capacitor or
transformer) that has a very high KVA and low watts (because the current and
voltage are out of phase with each other). For most devices KVA is about the
same as kilowatts.
For any device that you will connect to your generator, KVA will always be
greater than or equal to the kilowatts.
Lou Boyd
>
> pepto...@lycosmail.com wrote:
>
> > On 8 Feb 2001 02:00:59 GMT, Dante'@inferno.net (Speaker to Animals)
> > wrote:
> >
> > >which is why inverters and smaller generators are speced in KVA
> > >instead of Watts..and this is a fun topic that we could spend months on,
> >
> > Without spending months on it, can you explain what is a KVA?
> >
> > Thanks.
>
> KVA's are kilo-volts-amps, which means KVA=V*A/1000.
NO! its multiplied by 1000, not divided!
KVA= V*A*1000
--
Lou Boyd
Speaker to Animals
bo...@fairborn.dakotacom.net says...
>
>NO! its multiplied by 1000, not divided!
>KVA= V*A*1000
>
>--
>Lou Boyd
Again.
But:
120V 60HZ @10A =1.2KVA
If the load is purely non reactive (or resistive)
120V 60HZ @10A =1200Watts, 1.2KW
If operated for 1 hour the power used would be
1KWH
If your loads consist of anything other than a resitor (ie space heater, or
"Standard" light bulb{although even its current vs voltage is a little
distorted from the change in resitnace as the bulb heats and cool on each
cycle,,don't laugh it was enough to cause my first auto power factor corrector
to cry)}, like appliences with electric motors, or HAC equipment, or poor;y
designed(almost all)PC switch mode pwer supplies, etc, then power factor can
be very important. An uncorrected ystem will consume muchmore energy then it
really uses. Requiring a much larger generator or inverter, (and battery
bank).
Why generate power to waste on phantom loads.
If you still think PF is not an isue, just call your local power utility and
ask them. They spend big bucks to correct the PF so as to reduce system
loading.
And we could bring up harmonics to really start the fun. Hint, veriable speed
motors uses converters that can produce harmonics that will cause a pole
mounted power transformer to explode. Been there, saw it and want to avoid
that type of nightmare.
Lou Boyd
>
> In article <3A8C0E7F...@fairborn.dakotacom.net>,
> bo...@fairborn.dakotacom.net says...
> >
> >NO! its multiplied by 1000, not divided!
> >KVA= V*A*1000
> >
> >--
> >Lou Boyd
> I was afraid to start this flame war.
> Again.
> But:
> 120V 60HZ @10A =1.2KVA
> If the load is purely non reactive (or resistive)
> 120V 60HZ @10A =1200Watts, 1.2KW
> If operated for 1 hour the power used would be
> 1KWH
NO, it would be 1.2 KWHR
Sheesh!.... Must be the "new math" :-)
> If your loads consist of anything other than a resitor (ie space heater, or
> "Standard" light bulb{although even its current vs voltage is a little
> distorted from the change in resitnace as the bulb heats and cool on each
> cycle,,don't laugh it was enough to cause my first auto power factor corrector
> to cry)}, like appliences with electric motors, or HAC equipment, or poor;y
> designed(almost all)PC switch mode pwer supplies, etc, then power factor can
> be very important. An uncorrected ystem will consume muchmore energy then it
> really uses. Requiring a much larger generator or inverter, (and battery
> bank).
> Why generate power to waste on phantom loads.
> If you still think PF is not an isue, just call your local power utility and
> ask them. They spend big bucks to correct the PF so as to reduce system
> loading.
> And we could bring up harmonics to really start the fun. Hint, veriable speed
> motors uses converters that can produce harmonics that will cause a pole
> mounted power transformer to explode. Been there, saw it and want to avoid
> that type of nightmare.
The reason people buy equipment with a power factor different than one
is because it's cheaper. Your entrance meter only reads the resistive
component. Tough for the power company so they have to pay for the
correction if they bother. They do correct for areas, but not for
individual residential users. If you generate your own power you should
be concerned, but in the case of things like PC supply you're pretty
well stuck with what you get. Everyone thinks sine wave inverters are
great but for some types of loads square wave inverters are just as good
and sometimes more efficient. For other types of loads a square wave
can cause the equipment not to work or even to smoke.
It's unlikely for the harmoncs reflected back from a load to overheat a
transformer. The mechanism by which an inverter can blow up a power
transformer is by producing high voltage spikes which can break down the
insulation between the transformer windings. Once started the arc is
fed from the power source, boils the coolant, and blows up. Lightning
can start such a condition too. I made a mess of a pole transformer in
my youth when I built a 10KW Tesla coil. It's input wasn't well
filtered, though it never drew excessive current. It was a spectacular
though short lived toy.
Mike Burns
Lou Boyd wrote:
> Speaker to Animals wrote:
> >
> > In article <3A8C0E7F...@fairborn.dakotacom.net>,
> > bo...@fairborn.dakotacom.net says...
> > >
> > >NO! its multiplied by 1000, not divided!
> > >KVA= V*A*1000
> > >
No, you're mistaken. It's divided by 1000. Look at your own example, below. :)
Lou Boyd
--
Lou Boyd
--
Lou Boyd
Fairborn Observatory
Speaker to Animals
bo...@fairborn.dakotacom.net says...
>
>That wasn't my example, and it's wrong too!
>--
>Lou Boyd
>
Was too excited over the hot spring to think all that clear.
When I can not do simple math it is time to chill out.
On harmonics, I saw a small factory that had just got it's first CAM
(computer assisted manufacture) machine. A big brute with about 6 multi horse
power vari speed motors. When it would run it would do "funny" things.
Like make the florescent lights growl. The owners brother asked me to take a
look/listen. On a hot (around 100 F) afternoon I stopped by. IT was
imppressive to watch it move 1/2" sheet metla around and cut/punch it.
And sure enough if any two (or more) otors were on, the lights would growl.
Like a sick or angry dog. I admitted that I had never seen/heard anythinglike
this. I commented it sounded like 30Hz or so energy was getting into the
lights. As I wasleaveing, just as I steped out the back door, there was a dull
"thump", and a bright falsh. One (of set of three phoase) transformers had
"went up". I decided to wait around. They killed the building power (main
breaker cut off). the fire department and utiity showed up at the same time.
The fire had gone out. The utility worked asked some simple questions. Like
"what new equipment have you bought recently". When they mentioned the CAM, he
asked was it a "whatever"?(name escapes me) They were (in)famous for casuing
this. The "cure" was two part. A much heavier ground, and some large inductors
to isolate the motors fromt he mains. The guy was sharp. I quized him about
PF, harmonics and ground currents. He said that as bad as CAMs were, they had
bigger problems with new TV transmitters and some data operations. IT appears
that most swithc mode power supplies are nasty. And produce all sorts of
garbbage that can really mess up a distribution system. I have seen ads for
"low PF" and "non harmonic" switch modes in some of the trade electronic
magazines.
Lou Boyd
which regulate them had laws regulating the harmonic content of the
current drawn by users. Perhaps some do. I've never seen such a
specification. Without it I don't see what recourse the utility has
other than to replace the transformer and perhaps install shunt
capacitors which would reflect the current back to the user. That would
either cure the problem or smoke the users equipment.
I have a similar problem with an 18,000 watt inverter that drives a 1.5
horspower DC motor using an SCR controller. I need the intellegent
torque and velocity control it provides. If the inverter is heavily
loaded with an assortment of other motors, computers, etc it works fine,
but if the motor and controller are the only load the inverter sees the
odd current waveforms and shuts down. Fortunately it doesn't do damage
but the motor doesn't do it's job. I think I've found a cure by keeping
a single phase AC motor idling on the line to smooth the current
waveform.
--
Lou Boyd
Speaker to Animals wrote:
Speaker to Animals
bo...@fairborn.dakotacom.net says...
>
>It would make sense if power utilities and the regulatory commmissions
>which regulate them had laws regulating the harmonic content of the
>current drawn by users. Perhaps some do. I've never seen such a
>specification. Without it I don't see what recourse the utility has
>other than to replace the transformer and perhaps install shunt
>capacitors which would reflect the current back to the user. That would
>either cure the problem or smoke the users equipment.
>
>I have a similar problem with an 18,000 watt inverter that drives a 1.5
>horspower DC motor using an SCR controller. I need the intellegent
>torque and velocity control it provides. If the inverter is heavily
>loaded with an assortment of other motors, computers, etc it works fine,
>but if the motor and controller are the only load the inverter sees the
>odd current waveforms and shuts down. Fortunately it doesn't do damage
>but the motor doesn't do it's job. I think I've found a cure by keeping
>a single phase AC motor idling on the line to smooth the current
>waveform.
>--
>Lou Boyd
>
Youmight try a "brute force" filtering.
Since it is a SCR, feed it through a bridge that has an inductor on the
output. You can not use much in the way of capacitors on the DC side /(SCRs
will not turn off), but you can sure try some on the input.
Somehting like
AC---cap(10uF to nuetral)--inductor(1Hy in series)--cap(10uF to nuetral) to
bridge---inductor(1Hy in series)--SCR contoller.
A 100 watt light bulb, or a florescent light might alwao work.
A lot of factories use(d) (there are cheaper smart PF correctors)florescents
for PF correction.
OR
Drop back do a dumb simple saquare wave inverter. Some of the TrippLites(while
total junk they do work) will drive anything.
charles krin
>On 8 Feb 2001 02:00:59 GMT, Dante'@inferno.net (Speaker to Animals)
>wrote:
>
>>which is why inverters and smaller generators are speced in KVA
>>instead of Watts..and this is a fun topic that we could spend months on,
>
>Without spending months on it, can you explain what is a KVA?
>
>Thanks.
simply put, to do a true power level for AC, you need to use the
"average" voltage (also known as the "Root Mean Square" or RMS
voltage)...but for most purposes, the Volt*Amperage (literally the
expected supply voltage times the number of amps that you expect to
draw) or VA is close enough to the wattage.
KVA simple means KiloVoltAmps, or 1000 of the suckers...roughly a
kilowatt...
ck
--
Charles S. Krin, DO FAAFP,Member,PGBFH,KC5EVN
Email address dump file for spam: reply to ckrin at Iamerica dot net
F*S=k (Freedom times Security equals a constant: the more
security you have, the less freedom! Niven's Fourth Law)
Lou Boyd
>
> On Thu, 15 Feb 2001 08:52:35 +0000, pepto...@lycosmail.com wrote:
>
> >On 8 Feb 2001 02:00:59 GMT, Dante'@inferno.net (Speaker to Animals)
> >wrote:
> >
> >>which is why inverters and smaller generators are speced in KVA
> >>instead of Watts..and this is a fun topic that we could spend months on,
> >
> >Without spending months on it, can you explain what is a KVA?
> >
> >Thanks.
>
> simply put, to do a true power level for AC, you need to use the
> "average" voltage (also known as the "Root Mean Square" or RMS
> voltage)...but for most purposes, the Volt*Amperage (literally the
> expected supply voltage times the number of amps that you expect to
> draw) or VA is close enough to the wattage.
>
> KVA simple means KiloVoltAmps, or 1000 of the suckers...roughly a
> kilowatt...
>
across a 120 volt line you get 8.33 amps current flow which is a load of
1.0 KVA. The power delivered to the capacitor will be close to zero
watts. That's the whole point of the difference between Volt*Amperes
and Watts.
--
Lou Boyd