3D Printed Generator Build Highlights The Scientific Method

December 1, 2021 by Ryan Flowers 6 Comments

Sometimes we build to innovate, and sometimes we build just to have the satisfaction of saying we made it ourselves. Yet there is another reason to construct something ourselves: To learn, just as [Fraens] has done with this 3D-printed generator. (Video, embedded below.)

[Fraens] starts off with a jig for winding the individual coils, but then the jig itself snaps into a the stator ring. The stator ring is sandwiched by two rotors which rotate on a brass shaft suspended by needle bearings. With the exception of the hardware, all the structural parts are 3d printed.

What really separates the generator build isn’t how it’s built, but rather how [Fraens] has put it to use as tool for learning and experimentation. By plotting input torque vs electrical output, [Fraens] is able to calculate efficiencies in multiple configurations, and has some interesting conclusions to share toward the end of the video. We appreciate how the documentation and analysis help iterate the design towards higher efficiency and will inform the next build.

With some more work, we can see this going straight into a Vertical Axis Wind Turbine or attached to a Pelton Wheel for an off-grid hydro-power setup. Thanks to [Shabab] for the great Tip!

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Magnetic Bearings Put The Spin On This Flywheel Battery

July 22, 2021 by Dan Maloney 35 Comments

[Tom Stanton] is right about one thing: flywheels make excellent playthings. Whether watching a spinning top that never seems to slow down, or feeling the weird forces a gyroscope exerts, spinning things are oddly satisfying. And putting a flywheel to work as a battery makes it even cooler.

Of course, using a flywheel to store energy isn’t even close to being a new concept. But the principles [Tom] demonstrates in the video below, including the advantages of magnetically levitated bearings, are pretty cool to see all in one place. The flywheel itself is just a heavy aluminum disc on a shaft, with a pair of bearings on each side made of stacks of neodymium magnets. An additional low-friction thrust bearing at the end of the shaft keeps the systems suitably constrained, and allows the flywheel to spin for twelve minutes or more.

[Tom]’s next step was to harness some of the flywheel’s angular momentum to make electricity. He built a pair of rotors carrying more magnets, with a stator of custom-wound coils sandwiched between. A full-wave bridge rectifier and a capacitor complete the circuit and allow the flywheel to power a bunch of LEDs or even a small motor. The whole thing is nicely built and looks like a fun desk toy.

This is far from [Tom]’s first flywheel rodeo; his last foray into storing mechanical energy wasn’t terribly successful, but he has succeeded in making flywheels fly, one way or another.

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Black Starts: How The Grid Gets Restarted

July 15, 2021 by Dan Maloney 96 Comments

Gripped as we are at the time of this writing by a historic heatwave, it’s hard for those of us in the western United States to picture a time when cold and ice reigned across the land. But really, it was only about four months back that another bit of freakish weather was visited across most of the country, including places ill-equipped to deal with the consequences. The now-fabled “February Freeze” left millions, mostly in Texas, scrabbling about in the dark and cold as a series of cascading engineering failures took apart their electrical grid, piece by piece, county by county.

The event has been much discussed and dissected, as an event with such far-reaching impact should be. Like much discussion these days, precious little of it is either informed or civil, and that’s not good news for those seeking to understand what happened and how to prevent it from happening again, or at least to mitigate the effects somewhat. Part of that is understandable, given the life-disrupting and often life-threatening situations the disaster forced people to suddenly face. It’s also difficult for people to discuss an event so widespread in its scope and impact — there’s just too much for anyone to wrap their head around.

To make the present discussion a little easier, we’ll be focusing on one aspect of the February grid crash that’s often bandied about but rarely explained: that the Texas grid was mere minutes away from collapsing completely, and that it would have taken weeks or months to restore had it been able to slip away. Is that really possible? Can the power grid just “go away” completely and suddenly? The answer, sadly, is yes, but thankfully a lot of thought has been put into not only preventing it from happening but also how to restart everything if it does happen, by performing what’s known as a “Black Start.”

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Full Size 3D-Printed Wind Turbine

June 2, 2021 by Bryan Cockfield 29 Comments

Wind energy isn’t quite as common of an alternative energy source as solar, at least for small installations. It’s usually much easier just to throw a few panels and a battery together than it is to have a working turbine with many moving parts that need to be maintained when only a small amount of power is needed. However, if you find yourself where the wind blows but the sun don’t shine, there are a few new tools available to help create the most efficient wind turbine possible, provided you have a 3D printer.

[Jan] created this turbine with the help of QBlade, a piece of software that helps design turbine blades. It doesn’t have any support for 3D printing though, such as separating the blades into segments, infill, and attachment points, so [Jan] built YBlade to help take care of all of this and made the software available on the project’s GitHub page. The blades are only part of this story, though. [Jan] goes on to build a complete full-scale wind turbine that can generate nearly a kilowatt of power at peak production, although it does not currently have a generator attached and all of the energy gets converted to heat.

While we hope that future versions include a generator and perhaps even pitched blades to control rotor speed, [Jan] plans to focus his efforts into improving the blade design via the 3D printer. He is using an SLA printer for these builds, but presumably any type of printer would be up to the task of building a turbine like this. If you need inspiration for building a generator, take a look at this build which attempted to adapt a ceiling fan motor into a wind turbine generator.

The Dynamotor Simplified

April 11, 2021 by Al Williams 28 Comments

[Robert Murray-Smith] doesn’t like the price of inverters to convert DC to AC. That led him to build a dynamotor, or what is sometimes called a motor-generator set. These devices are just DC motors driving a generator. Of course, motors can also be used as generators and [Robert] had a stack of brushless motors in the form of PC fans. A two-fan dynamotor was born.

The brushless motors are attractive because, traditionally, the brushes are what usually fail on a dynamotor. The fan that will act as a generator needs some surgery, but it is simple. He scraped off all the control electronics and connected wires to the coils to form a three-phase generator. There’s no need for the fan blades in that configuration, either. If you were using ordinary motors and a generator, getting shafts concentric would be an important task. With the fans, it is simple to just line up the mounting holes and you get perfect alignment for free.

How does it work? [Robert] has a second video showing the output on a scope. You can see both videos below. The dynamotor makes a good-looking sine wave, probably much better than most reasonable-priced solid state inverters. He didn’t mention how much current he could successfully draw, but it probably isn’t much. You’d also need a transformer to replace a commercial inverter that would put out line voltage, so that would be some more loos in the system. On the other hand, if you wanted AC at a lower voltage, you might just replace all the transformers, if you were building a piece of gear yourself.

We’ve looked at how these things work in some detail. There were common in old tube radios, particularly military ones.

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Generator Runs On Natural Gas With Field Expedient Tip

March 3, 2021 by Tom Nardi 111 Comments

Many small gasoline engines can be safely modified to run on natural gas or propane with a kit that replaces the carburetor and adds a regulator, providing a reliable alternative fuel source in the event that gasoline is difficult to obtain in an emergency situation. This seat of the pants hack by [HowToLou] is definitively not the safe way to run your generator on natural gas, but if you ever find yourself in a situation where getting the power back on might be a literal matter of life or death, it’s a tip worth keeping in mind.

The basic idea here is that you feed natural gas (though propane should also work) directly into the engine’s intake by way of a hose attached to the air filter box. While cranking the engine, a valve on the gas line is used to manually adjust the air–fuel mixture until it fires up. It’s an extremely simple hack that, in a pinch, you can pull off with the parts on hand. But as you might expect, that simplicity comes at a cost.

There are a few big problems with this approach, but certainly the major one is that there’s nothing to cut off the flow of gas when the engine stops running. So if the generator stalls or you just forget to close the valve after you shut it down, there’s the potential for a very dangerous situation. Additionally, the manual gas valve will be at odds with a generator that automatically throttles up and down based on load. Though to be fair, there are certainly generators out there that simply run the engine flat-out the whole time.

Much like his DIY generator interlock plate that we covered last month, we imagine this project may rub some folks in the wrong way. Admittedly, this isn’t a modification that you should take lightly and certainly not something you’d want to rely on for long-term use. But as the recent situation in Texas has reminded us, drastic times can occasionally call for drastic measures.

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How To Design A Custom Generator Interlock Plate

February 22, 2021 by Tom Nardi 84 Comments

If you connect a generator to your home’s main electrical panel when the power goes out, you need to make sure the main breaker is shut off. Otherwise, when the power comes back on, you (or the linemen) are going to have a bad time. There are commercial interlock plates which physically prevent the generator and main breakers from being switched on at the same time, but since they tend to be expensive, [HowToLou] decided to make one himself.

The hardest part of this project is designing the template. It needs to be carefully shaped so its resting position prevents the generator’s breaker from being switched on under normal circumstances, but once the main is turned off and out of the way, you should be able to lift it up and have the clearance to flip the lower breaker. Spending some quality time at the breaker box with tape and a few pieces of cardboard is going to be the easiest way of finding the proper shape.

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