12VDC to 120VAC Grid-Tie Motor-Generator

Hi years ago an manufacturer named CARTER made a motor generator that was 12 volts dc in and 120 volts 60 hz output you would be better off with electronic unit check with harbor freight PERRY

The motor generator idea should work, and might hold synchronization better than a cheap inverter. However, I'd guess that you might be able to find an ordinary car or RV style inverter that would work, at least in the sense that some probably put out current that the power company would accept as being OK.... maybe. I'm guessing.

Or how about building a grid tie inverter that uses a boost circuit and and analog amplifier that uses the powerline frequency as a modulator? Speaking from ignorance (again), it seems like it could be fairly easy.

The utilities are usually rather fussy about what you tie into their grid and for good reason (safety and power quality). Generally, the complexity of these devices mean the economy of scale does not work out well for lower power levels. I suspect that even a home-grown MG set won't recoup the costs of 'selling back' power to the utility even at todays rising rates. They won't like your synchronous generator on-line either without an interrupter ($$).

an interrupter would not necessarily be costly, what about a spst/dpdt line voltage magnetic contactor for interruption, if line power goes down the switch opens?, that is not costly at all since most large ac motors use a type of magnetic switch such as this. i just love all the bench racing techies, from those who take no time or risk in attaining their dreams(as i and others have done). color outside the lines, maybe you will get somewhere in life, instead of shooting others ideas down, fyi, a synchronous a/c motor would naturally phase properly and supply the exact same waveform as the power plants do, most likely with better reliability than solid state. cudos to the guy who suggested this, hope my input helps.

Appreciate the feedback. Appreciate "Guests" feedback and encouragement too, but not the name calling and unconstructive attitude. The electrical output of a synchronous motor would be high quality, with little distortion. This is essentially how the utilities generate power, using synchronous generators. I suspect the grid-tie inverters (electronics based) produce more distortion. The main safety issue I hear stated is that during a power outage, a home generator back feeds the utilities system and energizes a line that the utility workers think is de-energized. Reality is that my little M-G set couldn't even carry the load at my house once the utility tripped, let alone re-energizing the utilities transformers, lines and my neighbors house. I would think an AC breaker would be adequate for protection. I'd just need to make sure I can generate enough current to trip the breaker! And I recognize the economics. If you want to minimize payback of a grid-tie solar system, you look at the tax incentives available in your state and then size your system accordingly. For me in Florida, the sweet spot is about a 2 kW system. *BUT* a system like that will still cost you $20,000 net out of pocket. That is not something many people would do. But a 250 watt system that costs maybe $2,000 based on a M-G might be something some people would do even though they may not qualify for tax incentives and is not the best option strictly looking at payback.

PS -- Just noticed on Ebay they are selling "250 WATT GRID TIE INVERTER FOR SOLAR PANELS OR WIND". Electronics based and currently listed for under $300. Just connect 2 solar panels and plug in to an outlet.

great idea, for further discussion please email me at mcculloughco@verizon.net , perhaps we could collaborate on a prototype that is affordable and safe for the marketplace-Pat

see my post to the bird(robin)brain below

The induction motor idea is interesting. I am looking at my electric bill and doing the math. I see that I could run a 3kw generator thru a grid tie into my main box for 36 hours straight at the end of my electric billing cycle and eliminate all my usage on the meter pushing my bill back to -0-$. This could be quite a simple task running it off natural gas or gasoline depending on the price of gasoline at the time. the AC motor would be a 2 or 3 wire motor and would be tied directly into the main breakerhowever.. I do have a 1kw sine w inverter DC to AC unit on my power back up. its not designed as a grid tie however.. would be the proper size to use an automotive alternator to feed 1kw into the box.. for say the last week of the month..

A Google search on "RPM independent grid tie induction generator" found one says it is; They also post pics -- It seems convincing.

http://www.google.com/search?sourceid=gmail&rls=gm&q=RPM%20independent%20grid%20tie%20induction%20generator

^{"...Reality is that my little M-G set couldn't even carry the load at my house once the utility tripped, let alone re-energizing the utilities transformers, lines and my neighbors house. I would think an AC breaker would be adequate for protection."}

I can "energize" a utility transformer backwards with a car battery and a pwm firing board, creating enough energy to kill an unsuspecting worker under the right circumstances. Size has little to do with it. The tried and tested rules of protection are not trivial by any stretch. Even with them, utility workers are killed every single day, it is a very hazardous job. Your idea, if universally implemented, potentially increases the risk of accidental exposure my millions! Think about it this way; if YOU were a linesman, and you had to connect a downed power line, would you want your life in the hands of any number of thousands of little generator systems built with the cheapest possible components made by people with any level of competence?

So Brave Sir Robin's comments, however disliked by the not-so-brave "guest" who remained anonymous, are accurate and reasonable. We are not speaking about trivial matters here, utility grid power has the potential to maim and kill the people who need to maintain it, a fact proven daily. Discounting their protection in the name of economy is tantamount to reckless disregard to human life..