motor madness

[Evan]

Nice work Darryl. I will have to try some of my own designs for my trike project this year since I am not happy with the commercial offerings. I ran out of time last year because of the footings drainage project from hell that ate my summer.

This is a rewound armature for a 90 volt treadmill motor to make it run on 24 volts. I went up two wire gauge sizes and reduced the number of turns by a third. That should raise the output to at least 2 hp but it cooks the brush holders if run very long at the level so I need to improve the brush holder plate.



This is a 4 speed 3 motor transmission that I built for my electric bike a couple of years ago. It worked but is too complex for good reliability so I took it apart.

[darryl]

This is another super magnet motor, an outer rotor 4 phase model. For scale, the aluminum channel piece that is the frame of it is 4 inches wide. On the top are four power mosfet transistors that drive the stationary windings.



A side view



Here it is from the back. At the bottom is the optical sensor array that times the switching of current into the four windings. The red bits are reflective stick-ons that control the optical tr sensors (transmit/receive).



This motor could handle more power than the mosfet devices are capable of delivering without cooking. You absolutely must hold on tightly upon start-up or it's gone. It's not particularly fast, but the torque is unbelievable - and so is the cogging at rest. It takes a pretty good twist to rotate it by hand. Once it's running it's smooth. This one would be good for a high torque, short operational time use. It does get hot after a while.

Well, there's a few examples from one of my hobbies- just thought I'd show something a bit different.

[darryl]

I know you guys like pictures, so here's a few of the electric motors I've made for fun. This one is a sort of stripped down satellite actuator motor, which I've rewound and re-brushed. It has triple brushes per side floating independently. The thinking was that it would increase the current handling capacity without increasing the size of the commutator. It achieves that goal, probably by eliminating the arcing that normally occurs when single brushes are used. The metal case has been stripped down to little more than the length of the original magnets, and the armature wiring has been epoxied and wrapped with who knows what- some damn strong fiber of some kind anyway, to help keep the windings in place at speed. It was designed for a model boat, which has since been scrapped because it split apart and almost sank before I got to it with the canoe.



Here's one of the largest motors I've ever built. At the time, plywood and fiberglass were my friends, and I had all these ceramic magnets laying around doing nothing. It powers up pretty good, but it's certainly not powerful for its size. I can't think of one thing that it's good for-



Not the smallest, but certainly powerful for its size, this is a re-built shaver motor, which now has super magnets and ball bearings, plus a fairly well heatsinked pair of brushes. I've clocked it at over 50,000 rpm on 12v. It will jump out of your hands when you first power it up if you're not holding on to it. This is the fastest rotating motor I've built, but not the fastest I've had one operating- that record stands at 85,000 rpm for a cd player motor running on about 90 odd volts just before it blew.