Rebuilding A Fried Fan Motor

May 22, 2012 by Mike Szczys 53 Comments

The fan motor on [Pete’s] oscillating tower fan conked out on him. It’s a shame to throw away the whole thing, but it’s near impossible to source parts for a small appliance like this one. So he set out to rebuilt the motor and get the thing working like new.

The motor in question is of the brushless AC variety. [Pete’s] gut told him that the failure was due to bad lubrication of the bearings at the factory. It stopped working because the commutator could no longer rotate freely. A check of the continuity of each of the coils led him to this thermal fuse. When the motor seized the AC current built up a lot of heat. This fuse is made to burn out before a fire can start but now it needs to be replaced. With a new one in place he reassembled the motor, making sure to pack the bearings with some quality lubricant. Now he’s once again ready for a long hot summer.

The Trials Of Working With Brushless DC Motors For The First Time.

May 12, 2012 by Caleb Kraft 9 Comments

We’ve all worked with DC motors at some point. Even if you aren’t a big hardware person, you’ve probably at least picked up a motor as a kid and touched a battery to the leads causing it to whir to life. These are usually standard DC motors and not their brushless relatives. Brushless motors require a bit more work since you are manually controlling things that are normally taken care of with the brushes. This article won’t teach you how, rather it will show you the mistakes one person made in his inaugural effort to use them. It is mildly amusing, but the project summary that he’s using them for seems even more interesting.

The job that’s been paying my bills and keeping me away from artsy-fartsy circuits for the past six months involves making a set of these enormous robot doors for a Certain Very Fancy Person’s house. Each door is 13 feet tall, around 7 feet wide, and weighs 1500 pounds. There are 66 of them in said house, and more in the servant quarters(!?!). The circuits on board each door have to handle running an onboard air compressor (which regulates a pneumatic weatherseal) as well as keeping track of temperature to linearize the pressure sensors when the weather gets cold. They also have to charge and maintain sealed lead acid batteries. They have commutated power rails. They have to communicate over said power rails, and do so using an capacitively-coupled data slicer and a proprietary protocol I wrote. This protocol has to be robust enough to bootload the processor over. It’s a proper embedded systems job.

Wow.

[via Adafruit]

Arduino Electronic Speed Control Explained

November 26, 2010 by Mike Szczys 29 Comments

You can salvage some nice motors out of optical drives but they can be tricky to control. That’s because brushless DC motors require carefully timed signals used in a process called Electronic Speed Control (ESC). [Fileark] built and ESC using an Arduino and has a couple of posts explaining the concept and demonstrating how it works. His test circuit uses six 2N2222 transistors to protect the Arduino from excessive current. You can see six red LEDs above which are inline with the base of teach transistor. This gives visual feedback when a transistor is switched, a big help for troubleshooting your circuit.

Once you’ve seen the videos after the break you’ll probably come to the conclusion that this is an impractical way to use a brushless motor. But it is a wonderful way to learn about, and experiment with the concept of ESC. Chances are you can get your hands on an old optical drive for free, making this an inexpensive weekend project.

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Build Your Own Hub Motor

February 18, 2010 by Mike Szczys 52 Comments

Hub motors put the power inside of the wheel. [Teamtestbot] goes deep into the hows and whys of building these motors, from parts, to windings, to the math behind the power ratios. The working example puts an electric motor inside the rear wheel of a Razor scooter. Past projects used belts to transfer the work of the motor to the wheel of the scooter. By integrating the motor and the wheel you end up with a much cleaner looking product. Check out the motor testing and the scooter test drive after the break.

For more tips on building your own electric motors take a peek at the Fly Electric page we covered back in November.

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1480W Scooter Motor Guarantees Head Trauma

October 18, 2009 by Mike Szczys 79 Comments

[Jerome’s] been working on some improvements to an electric foot scooter he picked up from a friend. He ordered up a powerful brushless motor and some lithium batteries. His system uses a belt drive and at 33 volts it can reach 25 miles per hour.

He had some problems with too much torque when the motor was first started. This resulted in unintentional wheelies, which sounds really cool if you’re not the one trying to hang on to the scooter. [Jerome] is using an Arduino to control the system so he built in the ability to gradually ramp up the speed of the motor and also added the ability to control the speed via remote control. You should note in the video after the break that [Jerome] is test-piloting his build sans-helmet.

So, we spend a lifetime and countless sums of money filling our noggins with knowledge. This is a precarious investment since a rather small bump to the melon could corrupt all of that data and end the once spectacular cognitive power. If you’re smart enough to build a foot scooter that can go 25mph, be smart enough to wear a helmet when you ride on it!

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