24-09-2014 07:09

Gdeaver

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

Best thing about it is that it does not contain mercury. The bad thing about it is that it does not contain mercury.

24-09-2014 15:28

Jefferson

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

With integrated encoder mount!
Very nice.

24-09-2014 15:45

BBray_T1296

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

Edit: Nevermind I figured it out

24-09-2014 16:25

AdamHeard

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

These are my favorite COTS slip rings

24-09-2014 17:16

Tyler2517

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

That's my type of slip ring.

25-09-2014 02:28

asid61

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

Very sweet. Remember to keep in mind that a 0.002" clearance on a 3D printed object is akin to a "press fit" (true story) in metal.
What's the final weight on that thing? I love the integrated encoder BTW. Is it for CIM speed or rotation?

25-09-2014 11:53

Kevin Ainsworth

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

.43LBS as shown with encoder, the previous design using CIM brush assemblies was .72LBS. This version would be able to handle the power of one CIM motor. Using a single Bag Motor brush assembly for each CIM cable, with both brushes wired in parallel, would have the same surface area as the single CIM brush internal in the motor. Current capacity should be exactly the same as the CIM itself.

25-09-2014 22:51

BBray_T1296

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

Also note that (barring some ridiculous design) these will not be spinning nearly as fast as a motor has to. You may be dealing with <5 rotations per second pretty much always. Not the ~100rps of a motor

26-09-2014 01:12

pwnageNick

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

Here are some more images of the design to get a better view of what's going on:

Sorry for the large images.

Imgur Album

26-09-2014 14:20

Kevin Ainsworth

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

One of our concerns at first was the fact that there could be full current load with no rotation. In a motor the rotation cleans the brushes and uniformly wears the commutator. In a slip ring for a swerve unit the rotation could be described as sporadic. We were concerned with arcing, pitting of the commutator ring, fusing of the brush to the ring, etc. This is why we used clear polycarb housings on the original prototype. But after running the slip ring for extended test cycles and after disassembly and inspection we found there was no reason for our concerns.

26-09-2014 14:32

nuclearnerd

Re: pic: Team 2451 Pwnage Custom Bag Motor Slip Ring

I think this is brilliant - really clever engineering using mostly commercial components, with a few 3D printed adaptors.

I hope you are able to deploy them! It would be a shame to have such carefully designed and tested components outlawed on safety grounds, while sketchy mechanical assemblies (some holding back serious stored energy) skate through no problem.