Although new electric motor types are still being invented, the basic principle of an electric motor has changed little in the past century-and-a-half: a stator and a rotor built of magnetic materials plus a bunch of strategically-placed loops of wire. But getting even those basic ingredients right took a lot of experimentation by some of the greatest names in physics. Michael Faraday was one of them, and in the process became the first person to turn electricity into motion. [Markus Bindhammer] has recreated Faraday’s experiment in proper 19th century style.
Back in 1821, the very nature of electricity and its relation to magnetism were active areas of research. Tasked with writing an article about the new science of eletromagnetics, Faraday decided to test out the interaction between a current-carrying wire and a permanent magnet, in a setup very similar to [Markus]’s design. A brass wire is hanging freely from a horizontal rod and makes contact with a conductive liquid, inside of which a magnet is standing vertically. As an electric current is passed through the wire, it begins to rotate around the magnet, as if to stir the liquid.
[Markus]’s video, embedded after the break, shows the entire construction process. Starting from rods and sheet metal, [Markus] uses mostly hand tools to create all basic parts that implement the motor, including a neat knife switch. Where Faraday used mercury as the conductive liquid, [Markus] uses salt water – cheaper and less toxic, although it does eventually eat up the brass wire through electrolysis.
While not particularly useful in itself, Faraday’s motor proved for the first time that electric energy could be converted into motion through magnetism, leading to a whole class of ultra-simple motors called homopolar motors. It would be a while before experiments by the likes of Tesla and Ferraris led to modern AC motors. If you don’t like your motors magnetic, you can use electrostatics instead.
Continue reading “Replicating Faraday’s 200-Year-Old Electric Motor”
Go-karts are a huge amount of fun, but often lack the most basic of mechanical conveniences such as a reverse gear. You can’t start a small four-stroke engine in reverse, so their simple chain drive transmissions lack the extra cogs to make it happen. Enter [HowToLou], who has given his go-kart a reversing option by the addition of an electric motor.
It’s an extremely simple arrangement, the motor is a geared 12 V item which drives a V-belt to the axle. The motor is mounted on a pivot with a lever, such that normally the belt isn’t engaged, thus reverse can be selected by pulling the lever. A simple button switch applies power to the motor, meaning that the machine can travel sedately backwards on electric power.
We’re not entirely convinced by the integrity of some of his fixings and it would be interesting to see how much the V-belt wears under the influence of the pulley when not engaged, but as an alternative to a full gearbox we can see the point. But then again as regular readers may know, we’re more used to full electric traction.
Continue reading “Go-Kart Reverse Without The Pain”
Starter motors aren’t typically a great choice for motorized projects, as they’re designed to give engines a big strong kick for a few seconds. Driving them continuously can often quickly overheat them and burn them out. However, [Austin Blake] demonstrates that by choosing parts carefully, you can indeed have some fun with a starter motor-powered ride.
[Austin] decided to equip his drift trike with a 42MT-equivalent starter motor typically used in heavy construction machinery. The motor was first stripped of its solenoid mechanism, which is used to disengage the starter from an engine after it has started. The housing was then machined down to make the motor smaller, and a mount designed to hold the starter on the drift trike’s frame.
A 36V battery pack was whipped up using some cells [Austin] had lying around, and fitted with a BMS for safe charging. The 12V starter can draw up to 1650 amps when cranking an engine, though the battery pack can only safely deliver 120 amps continuously. A Kelly controller for brushed DC motors was used, set up with a current limit to protect the battery from excessive current draw.
The hefty motor weighs around 50 pounds, and is by no way the lightest or most efficient drive solution out there. However, [Austin] reports that it has held up just fine in 20 minutes of near-continuous testing, despite being overvolted well beyond its design specification. The fact it’s operating at a tenth of its rated current may also have something to do with its longevity. It also bears noting that many YouTube EVs die shortly after they’re posted. Your mileage may vary.
For a more modern solution, you might consider converting an alternator into a brushless electric motor. Video after the break.
Continue reading “Heavy-Duty Starter Motor Powers An Awesome Drift Trike”
Back in high school, all the serious gearheads used to brag about two things: their drag strip tickets, and their dynamometer reports. The former showed how fast their muscle car could cover a quarter-mile, while the latter was documentation on how much power their carefully crafted machine could deliver. What can I say; gas was cheap and we didn’t have the Internet to distract us.
Bragging rights are not exactly what [Jeremy Fielding] has in mind for his DIY dynamometer, nor is getting the particulars on a big Detroit V8 engine. Rather, he wants to characterize small- to medium-sized electric motors, with an eye toward repurposing them for different projects. To do this, he built a simple jig to measure the two parameters needed to calculate the power output of a motor: speed and torque. A magnetic tachometer does the job of measuring the motor’s speed, but torque proved a bit more challenging. The motor under test is coupled to a separate electric braking motor, which spins free when it’s not powered. A lever arm of known length connects to the braking motor on one end while bearing on a digital scale on the other. With the motor under test spun up, the braking motor is gradually powered, which rotates its housing and produces a force on the scale through the lever arm. A little math is all it takes for the mystery motor to reveal its secrets.
[Jeremy]’s videos are always instructional, and the joy he obviously feels at discovery is infectious, so we’re surprised to see that we haven’t featured any of his stuff before. We’ve seen our share of dynos before, though, from the tiny to the computerized to the kind that sometimes blows up.
Continue reading “This DIY Dynamometer Shows Just What A Motor Can Do”
Messing about in boats has always held a curious appeal for the hardware hacker. Perhaps that’s because it remains an approachable way to make something that moves under its own power with a bit of speed, and barring calamities, the worst that can happen to the unwary boater is a soaking. [NASAT Channel] is a Vietnamese hacker who is a serial producer of small motorised boats, and one of his latest is a particularly impressive example.
The boat itself is a relatively conventional expanded polystyrene hull covered with fiberglass, but the motive power is something a little special. He’s taken eight of the ubiquitous 775 DC brushed motors and used them in a star configuration with beveled gears, which in turn drives a flexible shaft which goes straight to a propeller under the craft. Each motor shares a water cooling pipe serviced by a small pump, and the drive comes from a pair of cheap PWM motor controllers. We see him zipping up and down a stretch of river next to some moored boats, and if we’re honest, we wouldn’t mind a go ourselves.
We’re not entirely convinced such a rough-and-ready eight-way gearbox will be reliable for long-term use, and we’d be interested to know just how equally so many motors are actually sharing the load. But we like it for its sheer audacity, and we think you will too. Take a look at the video below the break, and if you’re inspired then grab a hammock, some friends, and have a go.
Continue reading “Eight Motors Speed This Boat Along”
Have you ever dreamed of flying, but lack the funds to buy your own airplane, the time to learn, or the whole hangar and airstrip thing? The answer might be in a class of ultralight aircraft called powered paragliders, which consist of a soft inflatable wing and a motor on your back. As you may have guessed, the motor is known as a paramotor, and it’s probably one of the simplest powered aircraft in existence. Usually little more than big propeller, a handheld throttle, and a gas engine.
But not always. The OpenPPG project aims to create a low-cost paramotor with electronics and motors intended for heavyweight multicopters. It provides thrust comparable to gas paramotors for 20 to 40 minutes of flight time, all while being cheaper and easier to maintain. The whole project is open source, so if you don’t want to buy one of their kits or assembled versions, you’re free to use and remix the design into a personal aircraft of your own creation.
It’s still going to cost for a few thousand USD to get a complete paraglider going, but at least you won’t need to pay hangar fees. Thanks to the design which utilizes carbon fiber plates and some clever hinges, the whole thing folds up into a easier to transport and store shape than traditional paramotors with one large propeller. Plus it doesn’t hurt that it looks a lot cooler.
Not only are the motors and speed controls borrowed from the world of quadcopters, but so is the physical layout. A traditional paramotor suffers from a torque issue, as the big propeller wants to twist the motor (and the human daring enough to strap it to his or her back) in the opposite direction. This effect is compensated for in traditional gas-powered paramotor by doing things like mounting the motor at an angle to produce an offset thrust. But like a quadcopter the OpenPPG uses counter-rotating propellers which counteract each others thrust, removing the torque placed on the pilot and simplifying design of the paraglider as a whole.
If you still insist on the fixed-wing experience, you could always get some foam board and hope for the best.
[Thanks to Luke for the tip.]
Continue reading “Open Source Paramotor Using Quadcopter Tech”
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.
Continue reading “Rolling Out A Slick Rotary Phase Converter”