rotor

26 Articles

Semi-automated Winder Spins Rotors For Motors

August 17, 2018 by 8 Comments

What’s your secret evil plan? Are you looking for world domination by building a machine that can truly replicate itself? Or are you just tired of winding motor rotors and other coils by hand? Either way, this automated coil winder is something you’re probably going to need.

We jest in part, but it’s true that closing the loop on self-replicating machines means being able to make things like motors. And for either brushed or brushless motors, that means turning spools of wire into coils of some sort. [Mr Innovative]’s winder uses a 3D-printed tube to spin magnet wire around a rotor core. A stepper motor turns the spinner arm a specified number of times, pausing at the end so the operator can move the wire to make room for the next loop. The rotor then spins to the next position on its own stepper motor, and the winding continues. That manual step needs attention to make this a fully automated system, and we think the tension of the wire needs to be addressed so the windings are a bit tighter. But it’s still a nice start, and it gives us some ideas for related coil-winding projects.

Of course, not every motor needs wound coils. After all, brushless PCB motors with etched coils are a thing.

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The Current Advances Of PCB Motors

May 12, 2018 by 9 Comments

There’s something to be said about the falling costs of printed circuit boards over the last decade. It’s opened up the world of PCB art, yes, but it’s also allowed for some experimentation with laying down fine copper wires inside a laminate of fiberglass and epoxy. We can design our own capacitive touch sensors. If you’re really clever, you can put coils inside four-layer PCBs. If you’re exceptionally clever, you can add a few magnets and build a brushless motor out of a PCB.

We first saw [Carl]’s PCB motor at the beginning of the year, but since then we’ve started the Hackaday Prize, [Carl] entered this project in the Prize, and this project already made it to the final round. It’s really that awesome. Since the last update, [Carl] has been working on improving the efficiency and cost of this tiny PCB motor. Part of this comes from new magnets. Instead of a quartet of round magnets, [Carl] found some magnets that divide the rotor into four equal pieces. This gives the rotor a more uniform magnetic field across its entire area, and hopefully more power.

The first version of this 3D printed PCB motor used press-fit bushings and a metallic shaft. While this worked, an extra piece of metal will just drive up the cost of the completed motor. [Carl] has redesigned the shaft of the rotor to get rid of the metallic axle and replace it with a cleverly designed, 3D printed axle. That’s some very nice 3D printing going on here, and something that will make this motor very, very cheap.

Right now, [Carl] has a motor that can be made at any board house that can do four-layer PCBs, and he’s got a rotor that can be easily made with injection molding. The next step is closed-loop control of this motor. This is a challenge because the back-EMF generated by four layers of windings is a little weak. This could also be accomplished with a hall sensor, but for now, [Carl] has a working PCB motor. There’s really only one thing to do now — get the power output up so we can have real quadcopter badges without mucking around with tiny brushed motors.

[Carl] has put up a few videos describing how his PCB motor works; you can check those out below.
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A Brushless Motor On A PCB, Made From PCB

March 28, 2018 by 33 Comments

At Hackaday, we really appreciate it when new projects build on projects we’ve featured in the past. It’s great to be able to track back and see what inspires people to pick up someone else’s work and bring it to the next level or take it down a totally new path.

This PCB brushless motor is a great example of the soft collaboration that makes the Hackaday community so powerful. [bobricius] says he was inspired by this tiny PCB BLDC when he came up with his design. His write-up is still sparse at this point, but it looks like his motor is going to be used to drive a small robot. As with his inspiration, this motor has the stator coils etched right into the base PCB. But there are some significant improvements, like increasing the stator coil count from six to eight, as well as increasing the overall size of the motor. [bobricius] has also done away with the 3D-printed rotor of the original, opting to fabricate his rotor from stacked PCBs with cutouts for 5-mm neodymium magnets. We like the idea of using the same material throughout the motor, and it also raises the potential for stacking a second stator on the other side of the rotor, which might help mechanically and electrically. Even still, the prototype seems to hold its own in the video below.

This is [bobricius]’ second entry in the 2018 Hackaday Prize so far, after his not-a-Nixie tube display. Have you entered anything yet? Get to it! Prizes, achievements, and glory await.

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This Tiny Motor Is Built Into A PCB

January 24, 2018 by 53 Comments

Mounting a motor on a PCB is nothing new, right? But how about making the PCB itself part of the motor? That’s what [Carl Bugeja] has done with his brushless DC motor in a PCB project, and we think it’s pretty cool.

Details on [Carl]’s Hackaday.io page are a bit sparse at this point, but we’ve been in contact with him and he filled us in a little. The PCB contains the stator of the BLDC and acts as a mechanical support for the rotor’s bearing. There are six spiral coils etched into the PCB, each with about 40 turns. The coils are distributed around the axis; connected in a wye configuration, they drive a 3D-printed rotor that has four magnets pressed into it. You can see a brief test in the video below; it seems to suffer from a little axial wobble due to the single bearing, but that could be handled with a hat board supporting an upper bearing.

We see a lot of potential in this design. [Carl] mentions that the lack of cores in the coil limit it to low-torque applications, but it seems feasible to bore out the center of the coils and press-fit a ferrite slug. Adding SMD Hall sensors to the board for feedback would be feasible, too — in fact, an entire ESC and motor on one PCB could be possible as well. [Carl] has promised to keep the project page updated, and we’re looking forward to more on this one.

For a more traditional approach to printed motors, check out this giant 3D-printed BLDC.

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It’s An Angle Grinder! No, It’s A Floor Sander!

August 18, 2017 by 21 Comments

Faced with the potentially arduous task of sanding a wood floor, what would you do? Hire a pro? Rent the proper tools and do it yourself? Perhaps even shell out big bucks to buy professional grade tools? Or would you root around in your junk pile and slap together a quick and dirty floor sander from an old angle grinder?

That’s what [Donn DIY] did when looking at the wide expanse of fresh floorboards in his new sauna. Never one to take the easy way out, and apparently with a thing for angled gear boxes, [Donn DIY] took the guts out of a burnt-out angle grinder for his impromptu floor sander. A drill attached to the old motor rotor provides the spin, and a couple of pieces of scrap wood make the platen. Sandpaper strips are clamped between the discs, and as seen in the video below, the whole contraption does an admirable job.

We’ve seen lots of angle grinder hacks before, some useful, some silly. This one gets the job done and is a nice quick hack that speaks to the value of a well-stocked junk pile.

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3D-Printed Turbine Rotary Tool Tops 40,000 RPM

July 3, 2017 by 38 Comments

For your high speed, low torque needs, few things beat a rotary tool like a Dremel. The electric motor has its limits, though, they generally peak out at 35,000 rpm or so. Plus there’s the dust and the chips to deal with from whatever you’re Dremeling, so why not kill two birds with one stone and build a turbine-driven rotary tool attachment for your shop vac?

Another serious shortcoming of the electric Dremels that is addressed by [johnnyq90]’s 3D-printed turbine is the lack of that dentist’s office whine. His tool provides enough of that sound to trigger an attack of odontophobia as it tops out at 43,000 rpm. The turbine’s stator and rotors are 3D-printed, as is the body, inlet scoop, and adapter for the vacuum line. A shaft from an old rotary tool is reused, but a new one could be turned pretty easily. The video below shows the finished tool in action; there’ll no doubt be objections in the comments to ingesting dust, chips, and incandescent bits of metal, but our feeling is that the turbine will hold up to these challenges pretty well. Until it doesn’t, that is.

We like [johnnyq90]’s design style, which you may recall from his micro Tesla turbine or nitro-powered rotary tool. He sure likes things that spin fast.

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3D-Printed Halbach Motor Part Two: Tuning, Testing

June 30, 2017 by 8 Comments

Building your own Halbach-effect brushless DC motor is one thing. Making sure it won’t blow up in your face another matter, and watching how [Christoph Laimer] puts his motor to the test is instructive.

You’ll remember [Christoph]’s giant 3D-printed BLDC motor from a recent post where he gave the motor a quick test spin. That the motor held together under load despite not being balanced is a testament to the quality of his design and the quality of the prints. But not wishing to tempt fate, and having made a few design changes, [Christoph] wisely chose to perform a static balancing of the rotor. He also made some basic but careful measurements of the motor’s parameters, including the velocity constant (Kv) using an electric drill, voltmeter, and tachometer, and the torque using a 3D-printed lever arm and a kitchen scale. All his numbers led him to an overall efficiency of 80%, which is impressive.

[Christoph] is shipping his tested BLDC off to the folks at FliteTest, where he hopes they put it to good use. They probably will — although they might ask for three more for a helicarrier.

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