Workshop In An Alternate Homepower Environment

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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 themselves.

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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!
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wrote:

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

Same with us.

I see that that is not just a local thing.

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The US was coming out of a significant depression. There was no "manufacturing based economy" in 1935 or 1940. If anything, it was agriculture-based.
scott

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Me wrote:

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.
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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.
--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
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wrote:

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 corruption. The US may have pushed them towards Stalin by supporting the corrupt Nationalists.
Where's Hamei when you need him?
--
Cliff

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Glenn Ashmore wrote:

Glenn- I was looking at your site a while back.. Very Cool. How's it coming?
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That is because the contract didn't spell their name correctly like you did.

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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.
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On 2005-06-14 too_many snipped-for-privacy@yahoo.com said: >Newsgroups: alt.energy.homepower,rec.crafts.metalworking,rec. >woodworking >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 >off grid? >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. >TMT 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 charge.
Tom Willmon near Mountainair, (mid) New Mexico, USA
Net-Tamer V 1.12.0 - Registered
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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?
TMT
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3 Phase motors really aren't a problem if you just use a FreqDrive that is 1 Phase input and 3 Phase output.
Me
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I would agree but an VFD that is unnecessary is a current draw that is not needed.
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.
TMT
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Too_Many_Tools wrote:

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 options.
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 refrigeration compressors.
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 practical solution.
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.
Pete C.
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wrote:

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 http://www.windenergy.com/whisper_200.htm .

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 every milliamp.

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 shop.

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.
http://www.citlink.net/~wmbjk/images/horizontals%20only.jpg top 40' of a 65' free-standing wind generator tower (in progress)
http://www.citlink.net/~wmbjk/images/tower%20top.JPG tower nearly finished and erected http://www.citlink.net/~wmbjk/frank.htm cactus transport
Wayne
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wmbjk wrote:

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 also.
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 homepower environment.

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 steps.

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 conversion.

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 minutes.
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 sources.

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 battery string.

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 woodworking.

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 utilities...
Just out of curiosity how do you make a living?
Pete C.
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wrote:

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 citing?

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 picture.
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 diddling.

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 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&categoryW039&itemu24207277 , 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.
Wayne
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wind driven generator

Another fly in the oiment on your battery remark.....if batteries are so much effecient at storaging .Why are repair shop using air tools instead battery powered tools.

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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?
Wayne
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