Any ideas?
I’m thinking some sort of adhesive. I do however have doubts on how it will hold…
I’ve seen elsewhere that teams have used a gear or pulley system to increase the RPM of the CIM. Don’t know what type of impeller they were using, or whether that is an option for you.
If you have access to a lathe, you should probably be able to turn a little aluminum or steel collar for the CIM shaft. You could make it a press fit… but looking at what you’ve got there… you could probably just put a cotter pin through the whole thing (impeller, collar, CIM shaft) to hold it together.
If you don’t have access to a lathe…hmmm… a bit tougher decision.
Jason
You bring up a good point, so a CIM motor maxes out at a little under 5000 RPM, do you think a simple impeller + CIM will be able to create the suction needed to possess a soccer ball?
Also, just curious, do you know how people attached their rollers to their CIM’s?
There are already some threads on this, like this one http://www.chiefdelphi.com/forums/showthread.php?t=79895&highlight=cim+impeller
I don’t know if you’ve tried searching, but you can usually find things more quickly that way than by posting and waiting for a reply. Sometimes you’ll have to try using different search terms, and sorting through a bunch of irrelevant stuff, but it is almost always worth it.
As for attaching a CIM to a roller… presumably a ball magnet type roller… I’m not sure how many teams are using CIM’s to do that. We are using the FP motor with a Banebots P60 transmission, and have machined the roller to directly accept the output shaft of the tranny, so it both supports one end of the roller AND turns the whole thing at the same time.
No reason you couldn’t do that with a CIM, I suppose… but it might be a bit fast.
I think you’ll also find that we had the option of ordering some nice drive belts as part of the KoP this year.
Good luck figuring out some solutions… and with your searching!
Jason
We have threaded the shaft of a cim motor before. You need a 8mm die (or 5/16), and a good way of holding the motor shaft to keep it from turning when doing so. Its tricky but we got it to work on our 09 bot’s fan.
It is very unlikely that you will get enough suction (delta P) by direct driving an impeller with a CIM. We geared our impeller up 3:1 (the impeller turns 3 times as fast as the CIM motor) to get the necessary rpm. Also, you might look for a different impeller than the one pictured. That is a mixed flow (both axial and radial flow) impeller like what you might see in a turbocharger. This design is a compromise between flow and pressure. What you want is a pure radial flow impeller like you would find in a shop vac. Volume flow rate is not very important, you want to maximize pressure change. A large diameter, narrow cross section impeller will give you that. If you can find a 2-stage impeller, so much the better.
We used a shop vac. Removed everything but the impeller, housing, and motor. Then we removed the armature from the motor shaft with a press and mounted a toothed belt pulley on the motor shaft, another on the CIM, with a 3:1 increase in speed.
Tried gears first, but it was very loud.