Jtod,
Good post and some good ideas, too.  Even I have second thoughts on pneumatic actuators.
The rack needs about an inch of throw, and about 15 lbs of force.  It takes this much force to overide the governor spring.  I've measured the force with a digital fish scale. 16/20 oz won't do squat.

If you look back in the thread, you'll see two suggestions I've previously made:  Giant scale RC servos have enough torque to do this and also to operate a decompression pin.  Picaxe and other microcontrollers  have compatible servo control software already done for you.  It's a Basic command in Picaxe Basic.

For a fail safe shut down, I'd suggest the fuseable brass wire method I previously mentioned. This wire holds the end of the governor spring and is disconnected by frying it with 12volts.  I've tested this and it does work nicely. This could  be used for an emergency shut down in case the microprocessor didn't operate properly, with some extra logic and timers.

But in general, I think the odds of the microprocessor failing at the same time as the cooling system or some other mechnical failure is remote enough to be resonably ignored.  Or perhaps just have the more commonly used "sanity check" pulsed circuit that the processor must keep alive, else the emergency brass wire should be blown.  So if the microprocessor fails at any time- they rack will be closed.

I have found the Picaxe chips to be easy to use, very reliable and static resistant. I'm wrapping up a project using one for a remote fiber optic controlled cell phone, just updating schematics now.  Picaxe basic is ideal for a lister(oid) controller, as it's easily readable and requires no investment in development tools.  I must thank Mr. Lister for his suggestion that I look into them.  I'm not sure when I'll get to the auto start/shut down for my Listeroid, but when I do I'll be glad to provide the source code to anyone who wants it.  Then it could be readily changed for different actuators, sensors, etc.

Best Wishes,
Bruce M

When I was a lad just starting out I wrote software for an Air Force research lab. 
Two cases to illustrate Guys GIGO observation:

I found one statistical analysis package that had been modified by my boss which did not clear some variables following the entry of each data input set.  Thus when the data entry clerk worked all day, entering data collected from pilots in our most advanced in the world research flight simulator, by the end of the day the results were utter garbage.  I corrected this, but it had been used for 3 years prior, and no one ever relooked at the dozens of research papers and technical reports based on this bogus data.

I also wrote a financial package for monitoring our on-site contracts, expenses and their incremental funding.    It included color plots as I also wrote a flat bed plotter package.  It included a computer projection of future spending that was hilarious- it allowed the contracts manager to fudge his  previous anticipated spending profile for a contract so that the "computer projections" always showed his contracts to be "looking good" in full color. (The program assumed competence and convergence.)   We won awards for both the software and for our outstanding management- and no longer had to write lengthy reports explaining contract under/overages.  This is a "good" form of GIGO- my boss got to see what was going on with his contracts, had the source for the prediction software so new what to do to both cover his ass and get the contract expenses/funding where they should be.

As Guy pointed out- if you don't have and understand the source code, trusting a software package is risky  business.

I agree, Bob G, there are lots of good ways to make the off grid approach work.  One item that surprised me in my research was the failure rate of commercial inverters.  I've seen a few studies where 2-3 failures per year were the norm.  So lots of folks like to do at least some DC lighting for reliability sake.  I think that's the marine power mantra as well.

 I've worked on a number of super insulated home projects in my area. These homes have 8" walls or double framed walls (up to R35) and R60 attics, reduced glass, low E glass, thermal break windows and in insulated slabs.  They are using 1/8 of the normal recommended heating wattage, and this in a climate with teens at night, some 0 degree nightime temps and high winds.  For example one home with 1500SF is in floor heated (Pex) with a single element water heater (4500 watts).  This is excessive, other 900-1000 SI homes here with electric baseboards are doing fine on 2000 watts total.  Because of our 40 degree/day temperature swings, a superinsulated home with adequate interior mass here needs no AC to stay cool (70F or less)  in the summer, even though it might hit 100 degrees.  In several studies looking at total energy costs, SI homes have often beat far more complex and costly solar home designs.  Smart use of each is clearly beneficial.

I was surprised to do the calculations and find out that "energy independance" via PV/wind/battery can easily become a situation where you've shifted dependance from the power company to the battery company. The ongoing replacement cost on batteries for large systems is substantial.  So like Bob, I've thought a lot about reducing my power requirements substantially, and epecially my battery system size.  For me it's about affordable living, and using a Lister(oid) more often (big loads like the washing machine, cloudy days, keeping the battery discharge cycle to 25%) will save me money over the long haul. 

i'm single, disabled and mostly homebound, and also find 1000SF to be ample to my needs.  Even with a library, office and lots of storage space.  For my shop however, too much is never enough.  I'm doubling my shop to 1200SF. 

Bruce M
Snowflake, AZ
Metro 6/1

Does anyone know of a source for brushless DC motors (1/6-1/4hp), or a brushless DC boost pump?
I've not been able to find them despite a lot of googling.

Because of a variety of other design issues, I'm going for a 130VDC primary battery bank, plus some 12V DC for small loads like DC circ pumps.  (Load , PV panel and battery co-located).  Two big advantages for me- I can't use compact fluorescents because they bother my epilepsy so am stuck with incandescents and line voltage halogens.  Also 130vdc is compatible with many switching power supplies so no inverter is needed for computer gear (I'll replace those power supplies that aren't compatible or do my own DC-DC conversion.)  I have a prototype inverter on my bench (that still needs a bunch of work), for generating small amounts of AC from the 130VDC battery bank.

Most solar systems are tending toward higher voltages (48VDC) because of the wiring/loss issues.  It will not be too many years before even higher DC voltages are used and appliances will track this.  Right now the market is still small, and thus the emphasis on inverters to provide compatibility with cheap AC appliances and fluorrescent lighting.

The AGM batteries are starting to come down in cost now (clones from Vietnam and elsewhere) and I've seen some data that shows higher effeciencies for them in charging.  They are starting to become tempting.  Overcharge is a disaster for them, but they otherwise seem superior in all aspects (but cost).  Some folks in my areas using them on their solar systems have been very pleased, but they've only been in service for a few years.

Thanks,
Bruce M

Thanks.  A wee bit of pressure does seem a good idea at this elevation, and gravity is an easy way to get it. 

As Im about to set up my generator shed radiator, I'm particulary interested in this setup.

Having no pressure in the system would  be a big plus as far as leaks go- how could I manage that with my big (hopefully) fanless truck radiator/convection setup?

 Can I just cut the rad. cap  spring and then plumb the vent tube to the bottom an air vented expansion tank above the radiator?  What are the down sides of no pressure- especially at my 5400 ft operating elevation?

Bruce M
Snowflake, AZ

I got my 6/1 mounted on the floor today and exhaust plumbed through a 2x10" piece of flex pipe (the kind with stainless mesh inside and out but corrogated stainless imbetween) through a piece of double walled stove pipe through the wall.  The pipe slopes slightly downward from the engine so condensate won't run into the head.  Not much for condensation here in AZ anyway.

On the outside is where I'm hoping for some ideas.  I need to attach pipe and muffler to the flat gable end wall- which is steel barn siding.  I don't want to vibrate the wall. 

What about some sort of isolation mounts or ?  One thought I had was to concrete a piece of pipe into the ground which could be strapped/clamped  to the exhaust pipe, and would then bear the weight of the exterior pipe and muffler assembly.  Then the wall mounts (pipe is 6" away from wall to avoid blistering the paint) would only have to bear lateral loads from wind.  I'm not sure how to isolate the pipe from some sort of support brackets...

Your thoughts and ideas appreciated.

Bruce M
Snowflake, AZ
Metro 6/1