Thread: Fingers crossed it'll cut ally
There was an article in MEW (Feb 2008 issue, No 135 ) about making outrunner motors but there wasn't much about how to power them. I'm guessing that the 'servo tester' provides a PWM pulsetrain and the speed controller (is this aka an 'ESC'?) sees the pulsetrain and uses electromagick to provide a 3-phase supply to the motor.
it will be a while before i can report any findings on mine... i cant wait to see how jonathan gets on with that monster motor of his and what he gets with the "star/delta" wiring (i have no idea what that is and im just about burnt out on research)
Last edited by blackburn mark; 05-08-2010 at 03:32 PM.
Quickly sketched this to show aircraft vs cnc application for those interested:
(You could probably delete the 4.8V supply if using a BEC ESC)
Last edited by routercnc; 05-08-2010 at 09:25 PM. Reason: updated sketch
nice one... im not so good with the electronics but all this stuff is nice and modular,, for those that dont know BEC is just a set of 5v power leads coming out of your Electronic speed controller to run your servo tester
anyone using small motors (engraving) might get away with an old PC power supply... they have 5v and 12v coming out of them
A cheap way of providing the 5v supply is just using a 5v voltage regulator. Any would probably suffice since it's only providing a few miliamps in this application.
With regards to my big motor I think I could get away with the 100mm shaft collet holders. I'd probably get the 1/2" one and reduce it down to 12mm. The motor contains 4 bearings, 3 of which are 2112 bearings and one big 6089. I shouldn't be too difficult to change them but it is worth it? The biggest external diameter bearing that would fit without doing something imaginative is maybe 24mm. I can't find any angular contact bearings that would fit there.
I've been thinking of using this motor for a 4th axis / lathe but I wont go too off topic!
i was terrified of turning down an over sized shaft so i spent weeks looking for the right size, its being shipped as we speak
im gutted you didnt find a 150mm one, im convinced it would have been easy to stick double row A/C on the nose in a shallow housing,, ill find out as soon as my shaft turns up ill start doing a bit of turning
im not totaly convinced a double row A/C bearing will be tight enough for ally, the ones iv got dont feel like they have that much pre-load, i might end up stacking the two of them
4th axis... mmmm im thinking a 100mm rotary table with my 5th stepper melded to it
im not sure anything is off topic,, is it?
SWEEEET!!!! im intimidated,,, and its not just a drawing, youve made a start
are you not happy with the rotary table?
are the solenoids air?
EDIT: iv just spotted the wires
I'm happy enough with the rotary table - it's very well made. If you get one I'd advise a vertex one as I've used this and a bigger one at school and they're both good. It's good in that it uses a worm gear (90:1) which means it wont move when milling but equally the worm gear is bad as it severely limits the rpm I can run the table at. I'm making the new axis because I want it to double up as a CNC lathe. My mini lathe (C3 from arc euro) isn't up to much so I'm hoping this will be sturdier.
I've machined the shaft of the axis the same as the mini-lathe so it can take the same chucks. Ideally I would have gone for bigger than 80mm diameter for the shaft...but turning that down to 35mm for the bearings took long enough and annoyed my teacher at school a bit... any bigger would have been pushing my luck I think!!
Any ideas for materials to use for the disk brake are welcome. The brake will only be used to hold in position, not for stopping, so heat build-up isn't an issue.
I'll go and take another photo...
P.S. Someone's bound to point this out, so before they do...If you look carefully on the renders of the 4th axis you'll see the disk brake is impossible to assemble! I've since fixed that by putting the disk the other side of the flange.
Last edited by Jonathan; 05-08-2010 at 09:09 PM.
Ah, im with you on the speed issue, i think i get you with the large motor to,, im guessing you would be fitting a rotory encoder for position feedback if you use the large DC motor ? (im no expert with these)
for the brake i would be looking at a motorcyle cluch plate maybe, im not sure youll get the force with electric solenoids to lock it for milling though but thats my guesstimation... id be tempted to consider an actual disk brake and caliper... the caliper would have to be beautfully fitted and have oposing pistons (you couldnt have it floating like you do on a vehicle)
im really not sure though im just thinking out loud :)
By i2i in forum Tool & Tooling TechnologyReplies: 12Last Post: 21-02-2013, 07:47 AM
FOR SALE: 45 by 90 ally profileBy johngoodrich in forum Items For SaleReplies: 5Last Post: 13-09-2011, 05:45 PM
By robmurf in forum Projects, Jobs & RequestsReplies: 2Last Post: 01-09-2010, 12:16 PM
NEW MEMBER: anyone wanna quote me to cut some ally?! and....By robmurf in forum New Member IntroductionsReplies: 2Last Post: 01-09-2010, 09:31 AM
By irving2008 in forum General DiscussionReplies: 6Last Post: 18-01-2009, 09:15 AM