Power controller made safe

The power controller for the 240V AC centrifugal fan has now been packaged in an earthed metal casing.


The speed of any 240V AC motor can now be controlled from standstill all the way up to full speed.

Power controller for centrifugal fan

I happened upon a very useful AC power controller on eBay. The Kemo M028N power control cost about £22, which is a lot cheaper than the equivalent variac. The device can handle anything up to 4000 watts at 240V or 2000 watts at 110V. However, a heat sink and fan will have to be employed for high power devices.

The photo above shows a quick test using a light bulb. The light is dimmed to its lowest possible level. Now, I need to rewire my centrifugal fan to handle AC again, after converting it to DC a few weeks ago. At last I have a controlable fan. No more excuses to avoid completing my downdraught gasifier.

More fan progress

With many projects on the go, finding time to work on the wood gas project is not easy. Over the past two weeks a photovoltaic system had to be set up. However, it gave me the chance to run the car air conditioning fan on the deep cycle battery and the result was much more promising than running the fan on a wall wart. The fan is a little over-powered so I will need to add a potentiometer to slow the fan down.

The fan I constructed from an electric leaf blower, and built a plywood case for, is now running on an old converted 386 PC power supply. The power supply has a +12V and -12V output and I am using this to run the fan on 24V. That fan is a little under-powered.

Interestingly, the car fan doesn't work well on the PC supply unit and the converted leaf blower doesn't work well on the deep cycle battery. Maybe someone reading this article knows the answer why.

The next thing to do is to build a transition for the car fan so that it can be connected to my no-weld gasifier. At long last I might be firing up the no-weld gasifier during the next week or two. I shall buy some charcoal and run the gasifier as an updraught gasifier just to check the seals and the power of the fans. Then the gasifier will be re-plumbed as a downdraught gasifier if the fans are up to the task. Charcoal is to be used as the planned gasifier will be a small one and charcoal is better than wood for that purpose. Of course, charcoal will have to be made on-site in future.

Constructing a centrifugal fan #3

The fan is almost complete. All that is needed now is a way of taming its huge power. Controls for moderating air input and output will have to be constructed.

Update 1 - After discussing my problem with other wood gasers I have changed to a lower power DC supply. With a variable resistor I will be able to find the optimal speed. The next task will be to make a transition for the fan casing so it can be connected to the wood gasifier.

Update 2 - Well, the DC worked but made the fan rotate in the opposite direction. So I converted from AC to DC and from blower to vacuum cleaner. After some thought, I turned the coils round, that reversed the magnetic field and now we have a blower again. Now onto making a transition.

Constructing a centrifugal fan #2

The centrifugal fan is almost complete. As the fan runs on 240V AC a lot of care is being taken to make sure the fan does not endanger anyone.

The following photo shows the fan and a plywood former for a length of thin steel that will act as outside of the fan casing.

The next photo shows the rear of the fan with the AC motor. As you can see there are plenty of bolts holding everything together.

All that remains is for the front face and sides of the casing to be completed.

Automotive wood gas videos

Here are a series of five videos on YouTube, demonstrating how an automotive wood gas generator works. The most detailed videos I have seen.

National Geographic - Car running on wood - Part 1



National Geographic - Car running on wood - Part 2



National Geographic - Car running on wood - Part 3



National Geographic - Car running on wood - Part 4



National Geographic - Car running on wood - Part 5

Handbook of Biomass Downdraft Gasifier Engine Systems

I am adding the Handbook of Biomass Downdraft Gasifier Engine Systems to my list of gasification reading materials.

This document is available for sale on some websites but it's actually in the public domain.

The handbook covers all aspects of gasifier designing, building and use of woodgas as an engine fuel source.

PDF document - Handbook of Biomass Downdraft Gasifier Engine Systems