Power transfer to Rotating base? (Electric)
 

Hi guys !
I am new here and after some unsuccessful searches i decided to register and ask.
I have a 3D Printer and started printing some machinery with it.
I have lots of experience in R/C, so ESC, brushes, etc are words i'm very familiar with.


So on an Excavator, when running electric, how does everyone transfers power to the tracks through the rotation of the cabin ?

I found this model on Thingiverse made by Erdinger :
https://www.thingiverse.com/thing:50110

He uses washers and spring loaded wires to get power to the tracks.
4 wires needed for 2 servos, one ground(common), one positive(common) and then the 2 signals.

Problem is, i can't keep the contact reliable and sometimes the sparking makes my receiver enters failsafe (which i really dont like, those X8R are expensive !)

I found a part called a "Slip Ring" which does seem like the way to go.
I ordered 3 different sizes, all with 6 wires in them (i plan to add a blade at the front of the tracks so i'll need 5 and i like having a spare wire just in case)

Here's one of those i bought :
https://www.aliexpress.com/item/22mm...311.0.0.9uM54p

Anyone having success with similar/different things ?


Video for the curious (was all black but remade using yellow and grey):
https://www.youtube.com/watch?v=BSuhngWgPdk

https://img4.hostingpics.net/thumbs/...0728180312.jpg

Also, for the curious, i found a way using a Taranis X9D to make the servos act like cylinders, so they do not come back to center when i release the sticks. It was hard-to-find information and takes alot of customs switches and mixes but once done it's almost magic !
If anyone wants to know how, message me and i'll be happy to show you in details !!

Next project, probably this Tractor since i can't find a working bulldozer :
https://www.thingiverse.com/thing:1967086
https://img4.hostingpics.net/thumbs/...ewfeatured.jpg

Re: Power transfer to Rotating base? (Electric)
 

Sliprings generally like to have a nice coating of dielectric grease to help cut down on arcing.

There seem to be 2 ways to get power through the turntable: run a slip ring if the motors aren't going to overload it. Or seperate systems with an rx above in the house, and an rx below in the crawler.

Re: Power transfer to Rotating base? (Electric)
 

Not sure if i can open up those chinese rings to lube them :D but i got some dielectric grease on hand.
Heck, i might try and pump it inside through the seals with my grease gun needle :rolleyes:

I also thought of using some capacitors on either side of the ring but wonder if it would just create a bigger spark ??

In fact, the rings are rated for 2 amps per wire and i only need to power 2 tactic tsx45 servos

Yeah, on a roughly 1:20 scale plastic excavator, getting a full set of battery/bec/receiver down there seems pretty optimistic :D
I could probably get it done though, with a small ~800mah 2s Lipo, 8-10amp BEC and micro receiver.
Now the question is, can i control 2 receivers at the same time with my taranis :eek:
Can't sleep until i find out now, thanks alot !! :D

Re: Power transfer to Rotating base? (Electric)
 

Any idea what the brushes are made of? metal wire or carbon?

Do you think it's circuits arcing over, or brush float causing the problem? Arc likes dielectric. Float needs perfectly clean

I've been trying to find a build that still has pics, setup like smallhauls ''Unit cable-hoe". I think he just ran a 4aa pack, 2 servos, and the rx in the crawler.

Re: Power transfer to Rotating base? (Electric)
 

In fact my sparking problem comes from the fact that i'm using plain old washers sandwiched between plastic discs with a wire soldered to each and a piece of wire touching each on the outside. You can imagine that washers aren't the most round objects to begin with, most of them are pretty oval.

This is what i'm trying to correct using the Slip Rings that i ordered, which i did not receive yet. I just wonder if there are bearings in there because it's gonna replace my big pivot bearings in the upper body section and there's alot of force applied there.

Re: Power transfer to Rotating base? (Electric)
 

Such slip-ring as you link to on aliexpress works just fine for this purpose. Lot's of the same on ebay, some different sizes.

Re: Power transfer to Rotating base? (Electric)
 

Nice, can't wait to try it !