y3 Tri-Copter - with Tail Yaw Mechanism - |Build Log|

[makattack]

OUch. Sorry to hear about the ESC's burning up. I'm not clear. Did they burn while just connected to the receiver directly or connected to the MultiWii flight board? When you were doing the calibration, using the receiver direct connect method, did the motors run up ok?

Were the motors directly soldered to the ESC's or connected via bullet connectors? I have what I thought was a longish run of about 12cm to the ESC's, but 35-45cm does seem like quite a bit more. Still, I wouldn't think it would be a problem.

I also wouldn't think the tail servo refresh rate should affect the motors/esc's. I know it may sound silly, but with disconnecting, reconnecting leads/plugs, especially if tired or not paying attention, one might plug the wrong ESC or servo leads into the flight controller. I wouldn't think a servo refresh rate would be incompatible with the ESC's but I do think that a motor plugged into the tail servo pins might be bad because it would be sending a PWM rate of around 1500 to the ESC, which might put it in programming mode, or it might run the motor up once it's booted.

Sorry, but I'm sort of just making guesses at this point.

 

[FPVology]

WOW what a beautiful design. I can't believe I am only seeing this thread now. Great job man.

I am currently working on a custom tricopter design as well and feel you on some of the difficulties. Hope you get the issue figured out!

 

[LennyPane]

@mackattack
thanks for sharing your thoughts anyway. two brains are better than one

-it burned while connected to the multiwii. although from one sec to the next, the motors had difficulties starting up no matter what the esc's were connected to.
-the motors are soldered directly to the esc's. removed the bullets.
-i also don't think it has anything to do with the servo refresh rate, i just tried to get rid of variables in the programming. i was also very careful plugging in, i didnt remove the servo lead while testing, just the esc leads between reciever throttle channel and multiwii.

i had another idea. as i posted earlier, one esc already had burned up due to the flight controller being programmed wrong(it jumped the motors from 0 to 100 with the slightest input, which already destroyed one esc) maybe that lightly damaged the other ones.
also the esc that i replaced then, was the one that wasn't getting that hot in comparison... might be a clue.

anyways, the manufacturer said i can send them back and get a refund. any recommendations for some good quality esc's? dont care for the price anymore. seems to be a delicate part. maybe i'll buy 4 again and test one for cable length compatibility.

@FPVology thanks man

 

[jipp]

rotogeeks are said to be pretty much bullet proof.. and take a beating. come with BLheli, and also you can reprogram them if you like.. and if you solder up your motors backwards you can just flip them so they turn the other direction in the programing software. i plan on using them on a build soon.
http://rotorgeeks.com/index.php?route=product/category&path=34_43
chris.

 

[LennyPane]

cool, then i'll geht those! thanks chris!

 

[HawkMan]

I would check other sources for the burnt ESC's as well, I doubt the first one burnt because of rapid changes in input(output actually) it's what they do.

I'm not an electronics expert, though I should be, but it's a long time since I had that in school. but the most likely solution is either resistance or short on the outputs.

reistance could be that you need thicker wire for such a stretch of wire(you really need to get a cheap Multimeter, you can pick them up at lots of places for the sameprice as those cheap ESC's auto parts shops or hobby/diy shops or well lots of places), you can measure the resistance on the wires and ask some expert advice on the ohm values here or on RC groups if they're ok.

it could also be a fault in the motors, do they spin completely freely by hand ? I guess you can measure the reistance in the motor spools and between the different phases as well, but I have no clue what you would measre and how to interpret that so, there you need some better people.

For the short, again a multimeter is your friend, easiest is a continuity test, for start and basics you should just measure between your ground pane of your craft and all power output to the motors, both the driving power and the servo power for the ESC's you use as a BEC. and again, measure that the spools in the motors don't have a short or partial short. but you should get the answer to that in the previous test so again, ask more experty people for how to measure motors for faults


And yeah, check that you don't have any continuity or low resistance connection(basically resistance should be unlimited) between the 3 power wires to the motors. just in case. At the same time, also measure continuity and resistance from power input/outputs on your board and ESC's to the various carbon plates and arms. after all, carbon is conductive.

also was it the same ESC that blew both times ? that could easily indicate a motor issue.

tldr; get a multimeter, measure everything

 

[cranialrectosis]

-it burned while connected to the multiwii. although from one sec to the next, the motors had difficulties starting up no matter what the esc's were connected to.
-the motors are soldered directly to the esc's. removed the bullets.
-i also don't think it has anything to do with the servo refresh rate, i just tried to get rid of variables in the programming. i was also very careful plugging in, i didnt remove the servo lead while testing, just the esc leads between reciever throttle channel and multiwii.

If the motors had difficulties starting up, do you mean they jittered/shook?

Jittering is often the result of removing the bullets and trimming down the motor leads and not burning off any enamel that may be on the motor leads. It is almost always the result of a poor connection between the ESC and the motor.

If you push a motor that is jittering you can torch both the ESC and the motor. :black_eyed:

To find root cause, I would start by looking for cold solder joints on the ESC/motor pads.

 

[LennyPane]

@HawkMan
thanks man! yeah i suspect the resistance being the fault as well.. could also be the cause of the first one burning.
i'll get thicker wires and check everything with a multimeter, for sure. i did insulate everything from the carbon though, i don't think a short could be the problem. my soldering joints on the other hand could be.

it was a different esc that blew. first the left then the back arm esc.

the motors spin kind of freely (unconnencted). they spin in 'steps' as if the spools were magnetic inside, not completely free like a ball barring would.
is that normal? hope they're not fried as well and i have to buy new ones. its getting quite expensive now. but cheap china stuff is not the way to go i guess.. especially not for kinda experimental builds and first time builders.

@cranial
yeah they jittered, and only started up with a little help from me and more power, but worked well once they got turning. also the problems only started up after 20 minutes of tinkering. at first everything was fine.
i thought i did proper soldering joints, reflowed everything, used lots of solder etc.. it looked good, but i guess you never know unless you test it :/

 

[timpainter]

grafhite bearing for tricopter

Hi
I to have thought that an inboard servo was the way to go.
I have used an anodised 12mm clamp with shims between the faces, and bearing directly on the graphite ( carbon fibre tube arm)
the inboard end is supported by the servo bearings this Is very light and has surprisingly low friction under load.
offset motor mounts mean that centre of rotation is closer to centre of mass of the motor.
a second clamp to connect servo to the tube, it is drilled and taped for small screws to attach it to a servo arm.
I hope this inspires others to try this simple layout.





Tim
Just realised that the photo looks like a Y6 ? no it is a tilt tri sitting on a reflective glass table.

 

[LennyPane]

hey tim,
love this design, very simple and looking sturdy.
hows the servo holding up under the stress of flying and wind?
had the idea to attach the arm directly to the servo as well, but thought it might strip out the servo gearing. i think my design was a bit bigger and probably had more stress load though.