mathjax

2011-06-23

Small Motor: IT IS FUNCTIONAL

So this took way longer than it should have but it is done. Stats: ~74rpm/V, ~.13V*s/rad, R(line to line) ~.25ohms, 30-40A max cont. 
Oh, Motor you so crazy 
So it works yay. Down side is it has quite the no load draw at first it was around 6A but then it dropped to around 4A after a bit of breaking in. This high value is probably because some of slight bearing misalignment in addition to some tight lateral forces, they could really use some wave washers right now, currently their snap rings are up against the outer motor plate while the inner ring is on a lip on the stator. That combined with the fact that one of the bearings sustained some minor injuries in a bout of stubbornness and curiosity about how tightly you can fit a bearing in a hole before it dies. When forcing a bearing into an aluminum plate this apparently occurs past the point when the aluminum is just barely flaking from being pushed out by the bearing and the bearing  almost won't rotate from all of the stresses/strains. That poor bearing's suffering will not go in vain for the limited amount of knowledge gained. All subsequent bearings I get my hands on should be thankful for its sacrifices to science. enough of that angent though, Here's a video of the motor working:
video

 Buuuuut back to the rest of the motor, here is the full stator assembly wires. The wires are in a groundless wye configuration and are all tacked down with some hot glue to keep them from rubbing on the rotor.
mmmm statory
After the assembly was completed with wires soldered and the shaft press fit and epoxied in place. All that was needed to finish up the assembly was shove the end plates on the the magnet can with the stator in the middle. Since the stator /rotor are in an unstable equilibrium its damn near impossible just to line up the screw holes without a jig by hand. I found that loosely screwing in one screw followed  by popping the whole motor in a vise with the shaft axis parallel to the vise jaws and the most displaced portion of the stator in plane with the vise jaws and then tightening them. This rotates everything about the screw until the end plates, stator and screw holes are pretty much concentric on their respective axes allowing everything to be screwed together yielding a sexy completed torque machine. More shenanigans regarding the state of this motor will be posted in the future.
The aforementioned complete sexy torque machine

EDIT: changed title

2011-06-16

Small Motor: Building for Stupid

In addition to a large motor that will be created there is a small motor in the process of being built and by small I mean relatively small like with a 4" diameter stator rather than 10.5". This stator contains 18 slots and was wound in an AaABbBCcC pattern with x10 24 gauge wires in parallel. The large number of smaller gauge wires exist because the first time winding this stator the obnoxiously stiff properties of 16 gauge wire were discovered. Thicker wire tends to bow out around the poles making tight packing of wires difficult. To accompany said stator is x20 .25"*.5"^2 magnets with an air gap of ~.75mm.

Small Stator with shaft collar insert

Here's the small stator that shiny piece of aluminum in the middle is there because I didn't have any long 1.5'' diameter chunks of metal and wasn't about to buy any. Its an epoxied press fit with a make shift key, which is a steel peg glued into a hole milled on the the border of the press fit.

Small stator with milled peg hole and peg.
To  to make the stator mechanically complete on more object is needed : a shaft and not just any shaft, a shaft built for stupid and by built for stupid that is not to imply this motor is made for someone a bit slow. By built for stupid I mean both rugged and ridiculous to a stupid extent. Why? because having ridiculously over built things gives me the same satisfied feeling as holding a sledge hammer. From a similar perspective it also allows said motor to be ridden or used 'stupidly' purposes in which a less mechanically sound object would die a horrible death. Also from a practical stand point this motor has ~15gauge equivalent and will be wound in a wye configuration and needs room for that fat hunk of copper to come out somewhere. That being said this meager motor is getting a 20mm shaft.

Magnet can, stator and shaft
By their powers combined this thing will hopefully be completed soon.