[rusty959]

Originally Posted by neutron256

Sorry I haven't sent you my CAD design for the compressor backplate yet. I haven't logged on to my CAD PC in a few days. Today is the one day a week I go into the office but I'll try and remember to send it to you when I get home.
Thanks. And no rush, we won't be touching this until atleast the weekend.
If anyone else wants any of my CAD designs just PM me your email, and what file type you'd like. I work in RhinoCAD but can export to most file types. Eventually I'll post them for anyone who wants access, but they're still a work in progress and I don't like to post somethign that's half finished.

A couple of thoughts on the design:

-If you can seal the transmission housing it will probably extend the life of the gears greatly. At those speeds even a little dust can quickly tear them up.
I may consider some form of cover in the long run. I would like to get some airflow through because there will need to be some cooling of some form. Additionally I need to inspect the gears because as I said I don't expect them to last all that long.
-The connection between the top and bottom plate needs to be stronger (could be worked into a sealed housing)
Yes it definitely does, as I mentioned in my post. Those connections were one of those things I just told her needed to be there, we didn't discuss size.
-Are you running seperate ESC's for each motor? With this design even a slight variance in speed, and possibly just relitive position of the motor windings could cause the motors to end up fighting each other.
Yes, separate ESC's. This is a common concern I have heard from a few people. I am not worried about it. A freespinning motor will spin up to high rpm's with little throttle. What holds it back is a load, which also causes it to draw more current. Therefore all of the motors will try to increase the speed of the shaft, and so there isn't a chance of one being driven by another. Past extremely low motor speeds the individual pulses won't be distinquishable due to momentum and all that jazz, so also hopefully won't be a problem.
Multiple motors are sometimes used in a similar configuration in the RC world both in brushed and brushless configurations. One in specific is the Traxxas E-Maxx. But if it becomes a problem, well then I guess Ill have to figure something out, lol.
If I have some time I might play around with your design some in CAD and see what I can come up with. Something integrated into the backplate of the compressor shouldn't be too hard.
Feel free. I'd love to see what you can do, you are obviously a lot more experienced with CAD than I/my gf are.
I like the concept, but with the forces involved my gut tells me it will self destruct. It will be interesting to see the results.
Well, if it self destructs, yay science. lol. Ill either fix what went wrong or cut my losses.

Originally Posted by nonicname

rusty that's a great thought but wouldn't you think it's better to take baby steps and use 2 motors before you use 3?
Yes. I mentioned this in my post.
just for my piece of mind make sure the motor gears don't touch each other, only the motor main fan shaft.
There's is going to be a LOT of torque so you need to make sure those motor mounts are REALLY beefed up.
The motors will be firmly mounted to a plate and won't be able to move side to side, so they won't be able to touch. In the drawing I can still increase the large gear size another 20mm (they are 100 now) and still be fine, but like I said the angle makes it look closer.
Also it worries me that you say you guys don't have much experience with CAD. Gears are not joke. it's a very meticulous thing
to get to work just right.
I'm not planning on cutting my own gears. They are just there for sizing. The gears Ill be using are commonly available in the R/C world.
As far as the plates and all, the geometry is simple. If it takes us awhile to get it down on CAD, its not that big of a deal. Ill also be prototyping with a 3d printer so any discrepancies can be found pretty easily. Gear mesh will be able to be adjusted and set identically to how they do it in the R/C world.

I posted replies in red. I tried not to seem too blunt in my replies. Keep the criticism coming, The earlier I hear of potential issues I haven't thought of the better I can change my designs.