Johan’s wood boiler setup

Correct. All self contained.
An engine driven inverter-generator first makes a three phase wild frequency ~150-300 VAC. Spinning strong permanent magnets inside of a bell around statioary output coils.
This is just like the modern personal wind generators.
Engine RPM can be varied between ~2400 to 3000 RPM. The small Honda go up to 4400 RPM. The small Yamaha’s out to 5000 RPM.
That wild AC then gets transformed down. Then rectified to DC. That energy stored into very large capacitors. Those rapid cycled discharge, quartz clocked into the 50 or 60 hertz AC final output.
Yeah. Yeah S-e-e-m-s horribly complex. But all of these components have been worldwide usages proven now for nearly 40 years. JUST be sure and get 1st world quality! Pay the more for it. Some of the made-in-China is this. Read lots of users reviews.

Anyhow this allows the gasifies engine to operate at any RPM it can. If it is running it is producing some safe useable AC electricity wattage. Just like PV solar.
Synchronous generating you either have to relatively massively oversize the engine and AC generator head to be able to take any reasonable load adds, without voltage sagging and be able to have simple mechanical RPM controls for the frequency. J.O.'s route I believe.
Or go with complex DIY rapid response engine RPM load controllers. Learn to physically make these up. Do a lot of line-by-line programming. Then re-programming for your specific operating range of conditions.
Some here on the DOW do take this route. Even offer up the base programming.

I am an Inputs versus Outputs kinnda’ guy. I never did enjoy electronics hobbying. First on family dairies learned the we-all-work-here-and produce-you-cows pragmatism. Or you are shipped to the dog food factory. Took that into adult life with machinery, systems and even people. IF I’ve given you the Inputs . . . and you cannot give me the Outputs you are gone, replaced with another that says they can. Prove it. Churn through enough and you find the willing to work and produce regardless of the the normal range of conditions.
Once found: then is when I give it, or them, the personal loyalty and loving care. Second chances. Till death do us part. A warm bed by the woodstove glow. Make-do jobs when they are old and feeble.
Pragmatism does not have to be cruel.


Living in Sweden, heat for you home is the first priority. Then electricity for refrigeration and lights. I would never use an all things generator. I would use a generator for the heating system that is just large enough to run it and I would use inverter tech but also funnel it though a battery back up system or power station large enough to run the heater electrics for however long you will not be available to tend to the gasifier supply to the gen set. Some extra expense but well worth it. Frees you family from trying to do things that not that many manly types are capable of. Then a separate gen set for other house hold electrics. Never put all your eggs in one basket as they say. You heating system is a thing of beauty and your english is at least as good as mine. Well done.

Came back to add that SteveU makes a very good point about getting your heater generator set up with propane. Easy to do long term fuel storage and keeps you from having to focus on either gasifying a vehicle or a gen set. If the vehicle is your first priority then your propane will keep your warm while you are getting wood gas to the generator. Again, options are good.


Thnk you for the kind words

Yes, this is also a very good point

And I like options, all options have to be on the table, only then can I make an informed decition (as long as I understand the options)

I will measure the amperes on the boiler and pumps so I have something to go on.


Absolutely, I now check a lot of reviews before I buy anything that I expect to perform, got sick and tired of buying crap and then have to buy another crap thing, I believe that quality pays off in the long run.
It also means that I have to take care of those things to keep them in good shape of course to make use of that quality.

For running the house a three phase inverter is preferred so not too much hassle has to happen, rerouting cables to the same phase and so on.
Now when I think of it I do have a pto-driven generator in one of the sheds but I am not sure if it is an inverter, will have to look in to that. If it is, then it is probably better to get an old gasoline tractor instead and get a gasifier on that. The tractors I do have are all diesels and I am a newbie in this so converting to spark plugs first and then a gasifier is not the thing I will start with. Lets see if I can get a car going on woodgas first and evolve from there. I get carried away sometimes

I think the generator in the shed is probably 35-40 years old, bought new by my grandpa as a backup for the milk cow farm


Don, sorry being late getting back to you, but I was busy last night getting the Volvo ready for today’s inspection. It payed off though. It’s good for another two years now :+1:

I’m not sure if you’re asking how well my setup works or what kind of generator I’m using.
Well, I can answer both.

The setup works very well, but the downside is I need to babysit the car. If something happens, the belt slips or brakes for example, the manual “hay string” throttle position setting will allow the engine to rev itself to death. Also, my cooler is not big enough sitting stationary for any longer period of time. Pretty warm gas enters the hay filter after a while.

My “generator” is actually a standard 3-phase asyncronous motor. Adding tourqe to the shaft just pushes power into the grid, which is providing a steady 50 Hz and rpm. It’s the simplest form of electricity generation, but of no use to me in case of a powerout since the grid provides the magnetic field needed.


Jan there’s means to setting up those motors with capacitors to self excite, but at the demand of home power it might lose its 50hz and sag down.

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That’s right Cody. I’m using capasitors, but only to keep reactive power and current down for the same useful power. In order to run it stand alone/self exiting mode you would need variable capasitors depending on load. Tricky in a diy setup.


However, if you come to a situation where the network fails, I can list some features of using an asynchronous motor as an independent generator:

  • if you have the option, choose a motor with high revolutions (2900 rpm), due to smaller reactive currents
  • a motor with a rated power of 9kW can produce 3kW of energy, that is, 3 times less than the rated power, this limits the reactive current that magnetizes the rotor, which is at least 3 times greater than the useful current
  • if we need a single-phase voltage, connect the capacitors in a star and thus get zero
  • the size of the capacitors really determines the load, but if we take this as an emergency solution, connect three capacitors with a capacitance of 100 micro farads in a star