There's still enough of us around that no how to make things to do it.
Unfortunaly, that won't be the case for too many more years. We're retiring.
A good example of the kind of thing that is wrecking the manufacturing base
is the place I presently work. Machine shop, run by an MBA. 50% of the
employees sit behind a desk. They wonder why they can't make any money. I've
been doing this since most of them were in grade school. When I have said
anything about getting more people producing and less people just collecting
a paycheck, I get put off as an old timer that just doesn't know how it's
done these days. Will be switching jobs here shortly. Let them go broke by
I've seen that a fair amount as well. At least at the place I work
now, the guys in the office still come out and run a machine from time
to time (the company only promotes from within, and only from those
who can perform every operation from the plasma-cutters to the mills
to the powder-coating line). I'm still young, so I bemoan the state
of manufacturing quite a bit- our average new employee is in and out
in less than a week, because nobody wants to get dirty, or get a
scratch on their soft, pretty skin anymore. Being a steel fabricator
used to be a respectable job because people understood that it is
skilled work- now it seems to be regarded as inferior to being a
night-time stocker at Walmart, if some of our ex-employees are
anything to go by.
Well, time will tell. I just keep hoarding tools and knowledge for
the day when I'm going to really, truly, need them. Of course, if
that day never comes- at least I've got an excellent hobby!
The place I'm at is a third generation family buiseness. If you are related,
they give you a desk, a computer and a paycheck. The olnly way I have seen
an outsider get in on this is to marry into the family.
>I'm still young, so I bemoan the state
I'm 45, considered an oldtimer as relativly few last in this buisiness
(small job shops) as long as I have.
>our average new employee is in and out
You think? It was the Nationalist Chinese we assisted in WWII, not the
Reds. IIRC, Mao and buddies didn't take over until '49, at which time
the Nationalists boogied to Formosa (aka Taiwan). The Reds have never
owed us anything but a hard time, in their philosophy, which they have
given us time after time.
Actually the US worked with both the Nationalists and the Communists during
WWII. The Chinese Communists were very helpful during WWII. The
Nationalist government, army and police were largely corrupt while the
Communist were much better disciplined and effective at fighting the
Japanese. That is also why it was so easy for them to chase the
Nationalists off the mainland. We supplied them with quite a bit of arms
and equipment. The communists returned any escaped POWs to US units while
the nationalist were just as likely to give them back to the Japanese if the
money was right.
It was only after the war when the Communists started gaining ground and Mao
aligned himself closer to Stalin that we started getting nervous.
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
Yep. Not that any of the wingers would know that. Or the
revisionists, working way at history in the US.
The Communists were the reformers. They'd had enough of
The US may have pushed them towards Stalin by supporting
the corrupt Nationalists.
Where's Hamei when you need him?
OMFG!! You have to be kidding me Mr Libertarian. The question is, do
you spend 2 billion at home, or in China? Do you honestly think it's a
good sign that we send $2 billion to foreign countries instead of
spending it here at home?
We have plenty of 3rd-world states here in the USA that could use $2
billion a day. I'm guessing that you live in one of them.
On 2005-06-14 too_many email@example.com said:
>I am posting this subject in three different groups to hopefully
>get a good cross section of ideas. I apologize ahead of time if
>this offends anyone.
>When one considers a workshop with metal and wood working
>capabilities, what tradeoffs have you made to have a working shop
>in an alternate homepower environment where every amp is precious?
>Obviously hand nonpowered tools take on a special importance.
>Cordless tools come to mind but which ones and what batteries?
>When considerng stationary tools like drills, lathes, mills, saws,
>grinders, etc., which ones fit best in an environment where one is
>Special operations like welding and using air compressors would
>seem to need consideration because of their unique requirements.
>I would be interested in hearing how others have approached this
>situation and what implementations they have adopted.
>Thanks for any suggestions or comments that you can offer.
My shop contains a 1HP air compressor (real, 1970's DeVilbiss), Miller
135amp 120volt MIG welder, metal lathe, drill press, radial-arm saw,
small table saw, assorted powered hand tools.
Because of all the motors, I chose a Trace sinewave inverter, 4KW to
cover starting surges (SW4024). Battery is 550 amp-hour, 24 volt,
T-105 golf cart, 3 parallel strings of 4 each. 1 KW of PV panels (16
Solarex 64 watt). System is in its 6th year of operation, supplying
household and work needs.
I work alone, so machines are run singly. Duty cycle is low; so is
energy consumption. I have yet to need to run a generator to cover
my working load, though I do use it to maintain the battery in our
rare cloudy weather, then avoiding power-intensive work.
When the shop was under construction, power initially was from the
generator. Most of the time is just sat, thrashing at no load, being
totally inefficient. Later construction was powered by the solar
system, blessedly silently recharging itself in between power draws.
When I have production welding, sand blasting, or intensive use of an
air-powered die grinder, I will probably have to use the generator,
passing power through the inverter and maintaining the battery
near Mountainair, (mid) New Mexico, USA
Net-Tamer V 1.12.0 - Registered
Thanks for posting...actual daily experience carries alot of weight.
What is the largest motor that your equipment has?
Any of them three phase? I ask because many times industrial equipment
has three phase motors.
Any desire for changing any of the motors to DC?
I would agree but an VFD that is unnecessary is a current draw that is
Like any system, one needs to plan a workshop as a whole.
At this point, I could go single phase, 3 phase or DC motors on on all
my machines. One of the reasons why I started this discussion was to
make that decision based partially on the experiences of others who
have hopefully gone before me.
I've been following this thread with some interest and now have some
thoughts and comments to add to it.
I may have missed something along the way, but I don't recall you
specifying what type(s) of alternative energy sources you have
available. This makes quite a difference in determining the best
As an example, if your alternate source(s) provide mechanical power such
as found with water power, wind power, or a solar boiler driving a
turbine or steam engine, then air power could be quite advantageous.
A source of mechanical energy can directly drive a compressor head,
saving the extremely inefficient conversions to electricity and back.
Compressed air is easy and economical to store in large volumes and is
free from the chemical hazards of batteries. Useable service life of
compressed air tanks is much higher than batteries as well.
In addition to the obvious air tools, compressed air can also be used to
power things such as refrigeration if you use the belt driven type
Those mechanical energy sources can also simultaneously drive electrical
generators to charge conventional batteries for loads such as lighting.
Battery charging for cordless tools is no less efficient that the
charging of your "regular" battery string, as long as the charging is
limited to peak energy generation times.
The efficiency of converting DC from your battery string to AC so you
can use conventional appliances is fairly good with modern inverters.
The conversion efficiency also improves when you use a higher voltage
battery string since inverters switching higher voltages at lower
currents will have lower resistive / heat losses.
Solar PV conversion efficiency is incredibly low to begin with and PV
cost is high so if that is your only energy source you really do need to
watch every miliamp. Of course, even with that inefficiency a solar PV
panel charging batteries for your cordless tools is just fine as long as
it has the capacity to keep up with your usage.
For items like welders that require huge gulps of power it's really
difficult to get away from an IC engine / generator for practicality. A
decent welder / generator can serve two needs and may be the most
If you've got really good water power available you could probably use
it to drive the head from an engine driven welder. A DC inverter type
welder could probably be modified to accept DC from a large battery
bank, but that would require you to have a fairly high voltage battery
string to be practical.
Someone else posted about the differences in energy needs of a shop vs.
home. They had more or less the correct idea, but got their terminology
a bit out of whack. A shop has mostly high peak energy loads at low duty
cycles and a home has mostly low peak loads with high duty cycles. The
total energy consumption over the course of a day could be similar
depending on how busy the shop is.
Wind driven compressor -> storage tank -> air motors? Could be OK if
one had a really windy site, lots of surplus pressure vessels, and a
plenty of rotor diameter. To get an idea of the diameter versus work
produced, check out the size and pumping rates of Bowjon well pumps.
Mechanical drive all the way to the pump? That would work well with a
large mill, when the wind is blowing, and be as efficient as these
http://www.deanbennett.com/windmills.htm . But in that application
there's the advantage of easy storage for when there's no wind.
Which is why the conventional rotor/alternator is so popular with home
power users. Ours is similar to this one
For the usual home power setup, cordless tools are no more and no less
advantageous than they are on-grid. Unless the power setup is very
small, the double conversion isn't worth trying to work around.
That depends. On very small systems, it's often true. Our setup isn't
huge, and costs about as much as a medium priced SUV. The idle loads
are about 100 Watts 24-7. That's a waste versus
convenience/practicality issue, and it's a long way from watching
Not necessarily. Home welding tends to be short duration. The hardware
to supply that kind of power is actually affordable, and if one is
designing the power system from scratch for what most would consider a
normal home, then the extra inverter capacity isn't a big deal. In our
case, for the house loads alone we could have gotten away with a
single SW4024 plus a transformer for the 220V loads. Instead we used
dual inverters, which eliminated the need for the transformer, and
provided sufficient power for most anything used in the usual home
Welder generators aren't a good match for backup duty, or even for
backup charging. Their advantage is portability for welding, and
they're only best (in the home power context) when you need high amps
for short periods. For any application that needs longer run times
supplying small loads, something like the Honda EU series is far
better. After a few years of living off-grid, like many others I found
that a DC backup generator that works independently of the
inverter/chargers is nice to have. The one I built drives a $5 scrap
Delco 27SI, and only produces about 2000 Watts. When there's no sun or
wind, we can do nicely on about 4 hours run time per day, at a
charging rate that's similar to when the other sources are on line.
Like some of the other comments in this thread (line shafts for
instance), that suggestion may be feasible. But unless one has way
more time than money, conventional methods are more practical.
That was probably me you're talking about, and my terminology was
quite correct for our setup. Occasionally our shop energy use is
higher than for our house, but usually it's the other way around by a
big margin. Normal power tool energy consumption in a home shop is
lost in the noise of an all-electric home's consumption. Welders,
plasma cutters, chop saws, table saws, planers, etc. are all high
power, but relatively low energy because of their short run times.
Keep in mind that we're talking *home* shop here, which I consider to
be small projects by one person. Many off-gridders go the route of
putting a high percentage of their loads onto propane, leaving much
less for the actual power system to do. For them, shop energy
consumption may indeed cause the need for a much larger system, or the
pain and cost of running a big generator. But we're very nearly 100%
solar/wind powered. We don't even have propane, and fuel use for
backup generator and the welder/generator combined isn't much
different than what some folks consume in a season of mowing a big
lawn with a garden tractor.
Here are a couple of my projects from my off-grid shop. I only needed
the engine-driven welder a few times, mostly for its portability.
top 40' of
a 65' free-standing wind generator tower (in progress)
finished and erected
http://www.citlink.net/~wmbjk/frank.htm cactus transport
Should be comparable or better efficiency than a wind driven generator
charging batteries. In either case you're capturing and storing the
intermittently produced power for later use and a more convenient rate.
A compressor powered by water or a solar steam generator would work well
Various electric utilities have been experimenting with compressed air
storage as a way to store power from excess generating capacity during
off peak times for use later during the peak times. They also do this
with pumped hydro, but CAS is far more practical than pumped hydro in a
No, not mechanically driven. The refrigeration compressor would be belt
driven from an air motor. The thermostat simply opens the air valve when
it needs to spin up the compressor. Again the ultimate source of power
does not have to be wind, and in fact with CAS it's even easier to
combine energy captured from multiple sources. No need to worry about
charge controllers when you're simply pumping air into a big tank.
The point is that batteries can only accept a charge at a certain rate,
potentially wasting captured energy during peaks. There is no such
limitation with an air tank, unless it's already at max capacity. Air
tanks are also a lot less expensive and lower maintenance than battery
strings. By combining both an electrical generator and an air compressor
on the wind plant you can better capture peak output.
The efficiency of directly utilizing the energy of the compressed air
for mechanical applications is also higher. Instead of capturing wind
energy, converting to electricity, storing in a battery, converting to
AC, converting to mechanical energy with a motor, converting to
compressed air with a compressor coupled to the motor and then utilizing
the compresses air to fire your nail gun, you eliminate four conversion
I know, but someone posted elsewhere in the thread that charging
cordless tools was horrifically inefficient.
This is where you really need the hybrid system. You run the inverter to
power your conventional appliances. When you are not running the
appliances you turn the inverter off. You run your lighting and TV and
whatnot that are your much higher duty cycle items from DC and avoid the
Perhaps your home welding is less than mine. I've got a Miller
Syncrowave 250 that I love and it can see quite a bit of use on project
weekends. I'm thinking your inverters would gag at the 240v 100a gulps
the Syncrowave takes, even if the typical gulp is only about 10 seconds
duration. On a big project those 10 second gulps add up to quite a few
I'm on-grid, but having recently moved to an area with much better solar
and wind potential I'm investigating options to take advantage of those
I didn't really intend the welder / generator to be used for backup to
the regular power system. I really meant it more as an option for
powering larger shop tools.
If you want to make it a bit more efficient in this capacity you can
build an automatic transfer switch so that when you are not drawing a
load from the generator to operate say a 5 hp table saw, the capacity
can be diverted to a charger to add some extra power to your regular
Modifying a DC inverter welder which are pretty inexpensive these days
is likely the most efficient way to get quality welding capacity from a
home power system. No line shaft required, and no need for oversized
inverters or load shedding.
Shop = big gulps, house = long sips :)
Well, my home shop which is just for me, includes a Bridgeport mill, a
metal lathe, the big honkin' TIG welder mentioned earlier, a CNC router,
60gal compressor, 10" table saw, an electric forklift and a host of
smaller items like sawsalls and grinders.
This is of course partly attributable to my preference for metal
projects which tend to require bigger tools and more power tools than
Nice projects. Someday I'd like to do that. Somehow it seems to cost
more to live self sufficient off-grid than it does to just pay the
Just out of curiosity how do you make a living?
Perhaps in some niches... but in any event a practical home power
setup needs some batteries, and charging them with wind, assuming
there's wind to harvest, is highly recommended. So you're talking
about *adding* systems because you believe it's worth the trouble, but
you haven't supplied any numbers or examples to back up your position.
But both are less practical than batteries.
How big a tank? I think you're going to find a fly in the ointment
once you run some numbers on air consumption. And if air power could
be so efficient and practical, why do you believe it is that
off-gridders, often known to be innovative and unafraid of breaking
with convention, haven't flocked to the concept?
There's isn't any peak power wasting problem that I'm aware of with
home power systems, since the cost of generating prevents people from
buying excess capacity. Can you give an example of the problem you're
You left out the AC to DC conversion of the turbine, and assumed that
energy used must be stored in a battery first. It's true that
compressed air for tools is a very inefficient process, on-grid or
off. Yet I've managed quite well with the just the same sort of
compressor that grid-connected folks use. I could do wind-powered shop
air more easily than most, but I wouldn't dream of adding another
system to cure an inefficiency that's such a small part of the big
Coincidentally, I have a neighbor who plans a Bowjon type installation
(low tower, bulky rotor, single-stage compressor) for shop air using
multiple surplus storage tanks. I've suggested that since he hasn't
any wind power at present and could really use some, that the time and
money he's going to put into the new setup would be better spent on a
conventional wind genny and a tall tower.
That's one of those convenience/practicalities tradeoffs. Many
appliances don't like being de-powered, and it's a nuisance to fight
it. IMO, biting the bullet for full time capacity is one of those
things that goes a long way to making off-grid living palatable for
the average person. After a hard day of pining over the dearth of
rural ballet, the last thing you want is to have to reprogram the
clock on the microwave. :-)
The conversion losses are lamentable, but not generally worth working
around. As Scott mentioned, after you've fought that battle for a
while, you're ready for straight AC in order to eliminate the
The fuses definitely couldn't handle it - 400A limit (24V system).
What kind of *home* welding are you doing that takes 24k Watts input?
People can size for whatever they can afford, but if I had the need
for more indoor stick/TIG, I'd be after one of these
which should be a comfortable fit with our setup. But I find I rarely
stick weld indoors above about 120A, although I use the Powemig 255 up
to its max more often. The only really heavy stuff I have to work on
are the tractors, and that's only occasionally. Since they don't fit
inside, and neither does the smoke and dust of heavy work, I roll an
engine-driven unit outdoors.
The auto-idle feature of a good unit will make that bearable, if the
tools' idle use is compatible. Still, the generator is going to be
either idling or roaring in between power tool use, at an average of
about $2 per hour in fuel. When we first moved onto our site, but
before we had the power system set up temporarily, I was stuck with
the welder generator. The running hours add up quickly, and I wouldn't
recommend it to anyone else except for occasional or temporary use, or
because there was no alternative, or if it's for a job that pays
enough to cover the expenses and aggravation.
Everyone has different needs, wants, and budget, but I think you'll
find that more and more people have a potential combination of house
loads that need such capacity that shop use isn't a leap. Around here
for instance are many who need to power the surge of a 2 hp well pump,
along with other use concurrent. It can be done with a smaller
inverter and a generator, but it's sure nice to get that generator
time down if you can. We used to have a couple nearby who had a
generator/battery/inverter setup, over 10 hours generator time per
day. That's about 4000 hours and 2000 gallons of fuel per year. I
think the fuel cost, repair costs, and eventual generator replacement
cost were big factors in their pulling out after a few years. Even a
modest amount of PV could have cut that generator time in half, and
would have been far cheaper in the long run. Better still, the cost of
that (very nice) generator and fuel could have bought a combination of
hardware including a much smaller generator needing only a few hours
per week run time.
Not necessarily. Cashing out of a grid-connected place allowed us to
retire, start with a clean slate, and as the yuppies say, "leverage"
the advantages of home power to help keep the big picture cost down.
Cheap land, lower taxes, fewer utilities (still need the phone
company) are some of the benefits. In talking to off-gridders, I find
that the main factor affecting success isn't so much the power issues,
but whether the folks can afford and are comfortable with truly rural
living. For most, that usually means retirement or telecommuting, and
precludes having children at home. For those who need to commute or be
close to school busses etc., they're usually stuck with paying the
premium for grid access. Then again, when they want to generate their
own power, they can have cheaper and more efficient systems, and use
the grid for storage.
On Fri, 17 Jun 2005 15:14:41 -0500, "Arnold Walker"
For the same reason that I use many air tools in my own shop - because
they're often lighter, cheaper, and more compact than electric
versions. Sometimes efficiency isn't very important.
Now, if compressed air is so much more efficient than batteries, then
why do *you* think that we're seeing ICE/battery hybrid cars driving
around, but not ICE/air hybrids?
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