Rolling Out A Slick Rotary Phase Converter

August 6, 2018 by Dan Maloney 46 Comments

Home machinists can often find great deals on used industrial equipment, and many a South Bend lathe or Bridgeport milling machine has followed someone home. Then comes the moment to plug it in, and the new owner discovers that the three-phase plug needed to power the new beast is nowhere to be found in the shop. Thus commences the weeping and the gnashing of teeth.

Luckily, [Handmade Extreme] is ahead of the curve in terms of shop power, and built a rotary phase converter to power his machines. Industry generally runs on three-phase AC systems, mainly because three-phase electric motors are so much more efficient and compact than the equivalent single-phase motor. But residential electrical service is either split-phase or, in the UK where [Handmade Extreme] is based, single phase. A rotary phase converter is an electromechanical device that can generate the missing phases – in essence a three-phase motor that can run on one winding and generate the missing phases across the other windings. It needs some supporting control circuitry to do so, such as timers and contactors to switch the winding connections once the motor starts, plus capacitors for motor starting and for balancing the voltage across the phases. The control gear is DIN-rail mounted and neatly wired to a smart-looking control panel. Everything is housed in a sturdy enclosure that’s big enough to serve as a mobile tool cart. It’s a really nice job – watch the whole build in the video below.

If you’re interested in power distribution, we’ve got a primer that covers the basics. And if you’re in the market for machine tools, [Quinn]’s machine tool buyer’s guide will let you decide if a three-phase machine is worth the extra effort.

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Here’s Why Hoverboard Motors Might Belong In Robots

February 3, 2018 by Donald Papp 28 Comments

[madcowswe] starts by pointing out that the entire premise of ODrive (an open-source brushless motor driver board) is to make use of inexpensive brushless motors in industrial-type applications. This usually means using hobby electric aircraft motors, but robotic applications sometimes need more torque than those motors can provide. Adding a gearbox is one option, but there is another: so-called “hoverboard” motors are common and offer a frankly outstanding torque-to-price ratio.

A teardown showed that the necessary mechanical and electrical interfacing look to be worth a try, so prototyping has begun. These motors are really designed for spinning a tire on the ground instead of driving other loads, but [madcowswe] believes that by adding an encoder and the right fixtures, these motors could form the basis of an excellent robot arm. The ODrive project was a contender for the 2016 Hackaday Prize and we can’t wait to see where this ends up.

Ben Franklin’s Weak Motor And Other Forgotten Locomotion

October 3, 2017 by Steven Dufresne 11 Comments

Most of the electric motors we see these days are of the electromagnetic variety, and for good reason: they’re powerful. But there’s a type of motor that was invented before the electromagnetic one, and of which there are many variations. Those are motors that run on high voltage, and the attraction and repulsion of charge, commonly known as electrostatic motors.

Ben Franklin — whose electric experiments are most frequently associated with flying a kite in a thunderstorm — built and tested one such high-voltage motor. It wasn’t very powerful, but was good enough for him to envision using it as a rotisserie hack. Food is a powerful motivator.

What follows is a walk through the development of various types of these motors, from the earliest ion propelled ones to the induction motors which most have never heard of before, even an HV hacker such as yours truly.

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DIY Electric Beach Luge Is A Thrill

August 23, 2017 by Donald Papp 14 Comments

[John Dingley] describes his Electric Beach Luge Project as an exciting mashup between “a downhill luge board, a kite surf buggy, a go-kart, and a Star Wars Land Speeder” and it’s fresh from a successful test run. What’s not to like? The DIY experimental vehicle was made to run on long, flat, firm stretches of sand while keeping the rider as close to the ground as possible. The Beach Luge is mainly intended to be ridden while lying on one’s back, luge-style, but it’s also possible to lay prone in the “Superman” position.

The whole unit was built from the ground up, but [John] points out that the design isn’t particularly complicated. There is no fancy self-balancing or suspension involved and steering is simple. A tube bender and a welder took care of making the frame. The rest is mainly used go-kart parts obtained cheaply from eBay, driven by a 500W 24V electric motor from an old Golf Kart. Like a luge sled, the goal is for the vehicle itself to interfere as little as possible between the user and the earth to make the experience as visceral as it can be.

You can see it in action in the two videos embedded below, but even more videos and some great pictures are available on the project’s page. [John] says it’s great fun to ride, but feels it could use twice as much power!

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Unconventional Homopolar Motor

February 13, 2017 by Manuel Rodriguez-Achach 37 Comments

As a hacker, chances are that you have built a homopolar motor, as you only need three things: a battery, a magnet and some copper wire. There are zillions of videos on YouTube. This time we want to show you [Electric Experiments Roobert33]´s version. Definitely a fresh twist on the ubiquitous design that you see everywhere. His design is a bit more complicated, but the result makes the effort worthwhile.

regla_mano_derecha_laplace — Right hand rule for the Lorenz force. By Jfmelero, via Wikimedia Commons

The homopolar motor was the first electric motor ever built. Created Michael Faraday in 1821, it works because of the Lorentz force. This force acts on any current-carrying conductor that is immersed in a magnetic field which is perpendicular to the current. These motors really have no practical applications, but are an excellent way to learn basic aspects of electromagnetism.

In this setup, there are two conductive rings placed above a wooden base, connected to the battery terminals. Neodymium magnets are connected by a conductive rod that pivots in the center of the rings, closing the circuit and allowing the flow of current. Then the Lorentz force makes its magic and pushes the rod and magnets in a circular motion.

Very clean and well-edited work, as are other videos by [Electric Experiments Roobert33]. You may want to replicate this nice motor, or you can also make the simpler version to start experimenting.

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Light Rider: A Lightweight 3D Printed Electric Motorcycle!

January 29, 2017 by James Hobson 43 Comments

It sounds like the name of a vehicle in some sci-fi tale, but that fiction is only a short leap from reality. Light Rider is, in fact, an electric motorcycle with a 3D printed frame that resembles an organic structure more than a machine.

Designed by the Airbus subsidiary [APWorks], the largely hollow frame was devised to minimize weight while maintaining its integrity and facilitating the integration of cables within the structure. The frame is printed by melting a sea aluminium alloy particles together into thousands of layers 30 microns thick. Overall, Light Rider’s frame weighs 30% less than similar bikes; its net weight — including motor — barely tips the scales at 35 kg. Its 6 kW motor is capable of propelling its rider to 45 km/h in three seconds with a top speed of 80 km/h, and a range of approximately 60 km — not too shabby for a prototype!

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Snowed-In In The City? The Snow Bike Will Get You Where You Need To Go

January 29, 2017 by James Hobson 20 Comments

If have ever gone snowmobiling, you may have thought about how to revive that thrill in the more confined atmosphere of an urban environment — to say nothing of their utility. In anticipation of heavy snowfall over the winter in his hometown, [Ben] stripped the essence of the snowmobile down as an emergency vehicle and reshaped it into the Snow Bike.

This compact, winter transportation solution uses an e-bike controller, a chopped up ski, and a heavy snowblower track and a large RC plane motor for power all strapped onto a modified mountain bike frame. The motor mount is machined aluminum, the track rollers milled out of spare plastic — though they later had to be modified as they tended to get clogged by snow — and the front ski is simply bolted on using some 3″ square tubing.

Due to its small size the Snow Bike looks about as stable as a pocket bike, so perhaps some training tracks and or skis might help in deeper powder. [Ben] also notes that the present motor doesn’t have much power so the rider needs to keep it at full throttle to push through the snow. That said — seeing this thing smoothly cruising around in several inches of snow makes us wish we had one of our own.

If this ride isn’t fast enough for you, check out these rocket-powered winter vehicles.

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