stator

17 Articles

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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Hand-Wound Brushless Motors Revive Grounded Quad

June 6, 2017 by 33 Comments

You’re happily FPVing through the wild blue yonder, dodging and jinking through the obstacles of your favorite quadcopter racing course. You get a shade too close to a branch and suddenly the picture in your goggles gets the shakes and your bird hits the dirt. Then you smell the smoke and you know what happened – a broken blade put a motor off-balance and burned out a winding in the stator.

What to do? A sensible pilot might send the quad to the healing bench for a motor replacement. But [BRADtheRipper] prefers to take the opportunity to rewind his burned-out brushless motors by hand, despite the fact that new ones costs all of five bucks. There’s some madness to his method, which he demonstrates in the video below, but there’s also some justification for the effort. [Brad]’s coil transplant recipient, a 2205 racing motor, was originally wound with doubled 28AWG magnet wire of unknown provenance. He chose to rewind it with high-quality 25AWG enameled wire, giving almost the same ampacity in a single, easier to handle and less fragile conductor. Plus, by varying the number of turns on each pole of the stator, he’s able to alter the motor’s performance.

In all, there are a bunch of nice tricks in here to file away for a rainy day. If you need to get up to speed on BLDC motor basics, check out this primer. Or you may just want to start 3D printing your own BLDC motors.

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Build Your Own Vertical Axis Wind Turbine

March 11, 2011 by 26 Comments

You can build a copy of this vertical wind turbine in a weekend and it won’t cost you all that much. Applied Sciences developed the hardware and they’re sharing all for the build details. You will be taken through every part of the build starting with the fin assembly which is made from stove-pipe material. This is a perfect raw material because it is already curved and suited for aerodynamic use in much the same way that PVC pipe is for making fins and we would expect it to be a bit lighter in weight. You will also need to turn your own coils when assembling the stator. This particular build process uses nine coils embedded in fiberglass. They remain stationary while two different discs, each containing a dozen rare earth magnets, rotate in close proximity to induce a current. It outputs three-phase AC current which can be turned to DC using a bridge rectifier and then further regulated for storage in batteries.

[Thanks Miguel]