Rango - Build diary

[Ellis]

Rofl^ / cheers guys, yeah it's a bitsy thing, about to get even bitsier with electronics mounting. Want to actually mount the internals in Rango, because some guy designed it with a load of belts going everywhere. Going to mean a lot of small standoffs and tiny plates!

Also, the wedge has been watercut, and Mario has already welded it up. He's doing some work for T2 as well, so it'll be couriered to here sometime next week, hopefully alongside. It's 3.2mm hardox and weighs 1kg.





It's slot-and-tab to make positioning for welding straightforward, and the mounting brackets are slotted so I can set the height depending on who I'm fighting, or leave it loose and have it *hopefully* completely ground-scraping.

The pulleys are now bolted to the wheels which allows me to see where exactly the belts will all pass, so I can now start to position internals around them and devise mounts. Not done much buildy stuff today, the chassis is on the floor and I'm throwing speed controllers at it to see how they fit.

[RoboLibre]

Looking good Ellis... like how your putting a lot of thought into everything =)

In regards to those motor shaft protectors... great idea, just make sure you get some full length sleeves/standoff tubes on those bolts if you can... will be much stronger if the base of the standoffs can press up against the motor casing rather than resting on the shaft bearing neck like you have now in the pic (will reduce unwanted sideways flex)

I'm assuming you have them where they currently are, because they are too large in external diameter to slide past the bearing neck, but if you get some longer standoffs, and use a grinder/dremel/flatfile... you'll be able to remove some material off of one side of the standoffs, so that they slide down to the motor case end.
Obviously you wouldn't need to file the whole side down, just the length that would need to pass the bearing neck on the motor casing.

Possibly overkill... but another thought might be to get a washer and a thrust bearing in between the gear face and the brass bushing you have there... then again it does look like you could be pressed for length on the protruding shaft *giggdy
so you could mill a larger hole in the brass bushing you have there, then lathe a brass collar that fits over the shaft but inside that recess in the end gear... then the thrust bearing could be cupped by your retainer and sit on the top face of the lathed brass sleeve.

If your gram counting and are wanting to be this meticulous, you could tack weld some needle bearing cartridges onto those steel plates you have holding the brass bushing instead...

food for thought, that my random 2 pence in anyways haha

[Ellis]

Hi RoboLibre. Thanks for the post. The standoffs fit fine and are free to go wherever, it looks like they clash but they are clear of the motor boss by miles. They're the short length they are because the 10mm thick motor mount plate (not yet made up) is what they tighten onto, and I can easily adjust their length for a nice frictionless support on the motor shaft. I don't think a bearing in there is worth it; space is very limited (12mm OD is the limit) and the bronze should last plenty long enough for a competition or two. Can always make up spares. I cleaned up the front of the pinions so that they are smooth, with a bit of grease wear should be minimal. The bronze doesn't even touch the gear under no load anyway.

Have tested the motor with and without the support and there is no audible difference, no heat in the bush and no apparent issue change in start up speed. That's without any grease.

It'll be just fine lol.

[Ellis]

Sorry for the double post. Been testing the electrical side of the machine, and have come across an issue. I suspect (and sincerely hope) the problem here is born from lack of knowledge and general noobiness. Any help appreciated.

https://www.youtube.com/watch?v=7RuAjHZU-6Q

I sound all racey in the video, was a bit disappointed, I wanted it to go whizz!

Thanks.

[adz600]

Are you phases correct on the motor, are they both matched ie non sensored, if so sounds like a dead motor never had that problem before on a model car setup ran many over the years

[Flag Captured]

Have you run it without the mount? Perhaps the mounting screws are causing the motor to stop turning... I know that's pretty unlikely, but it might be worth a check? If not, then I'm not sure what it could be other than a setup error or a dodgy motor

[RogueTwoRobots]

If the motor's getting that warm from that short time it was in use in the video, it would suggest that there may be a problem internally, something that's increasing the resistance. I'm pretty sure even the cheapest of brushless motors shouldn't get that warm that quickly. Could be something that hasn't been mounted concentrically on the shaft and is rubbing on the insides of the can or it could be, as Matt touched on, the mounting screws on the front are just a tad too long and are touching the internals.

Try it the same way as the Align, i.e. just being held in your hand without the mounting plate attached. If the problem still persists, then the motor's probably gubbed. It could just be some setting on the speed controller that needs adjusted but I reckon that's less likely since you've proven every other aspect of the setup with the Align motor connected.

[Ellis]

Thanks for the responses guys. Naturally, as I made the plate, I double and triple and quadruple checked the screw lengths, they're plenty out of the way, but I just tried it off the mount and it behaves the same.

The motor and ESC are both sensorless.

Reviews on HK are very positive for this motor, so I may do best to try and get another one, but naturally I'm put off. There aren't many alternatives in my price range, sadly. The Align is usable but I think the poor thing will give up before long, it's had a hard life. :P

Not sure what to do!

[harry hills]

By the time you kill the motor I'll be out of the competition so you can have Massacre's inrunner for silly speed. Or you can have the 35mm Outrunner of Shame

Buy another one asap, you're already in minus money so another 30 quid won't hurt (that's about what I owe you anyway :P)

[maddox10]

Put in the Align for testing.

Order another motor, and claim refund on the one you have.

[leorcc]

Sounds like you've lost a phase in the motor. That also accounts for the heat as it might short inside the can.

[Ellis]

I have spoken to a tech guy at Hobbyking, through their live chat system, and amazingly it was very useful. The guy was asking questions, watched the video, making suggestions, and very clearly knew his stuff. Got to hand it to HK, I'm pleasantly surprised.

He thought it might be ESC setup. I think by default the YEP150 is designed to run outrunners (the Align is in fact an outrunner enclosed in a case, I called it an inrunner to avoid confusion, this guy knew his stuff enough to point this out) which would make sense in that case. I don't have a programming card, but we're going to try and set up the PWM and timing to run the Turnigy as per his suggestions, via the Spektrum.

Will keep this posted, I hope we can solve it. Really don't want to have to get into ordering a replacement this late in the game!

[Mouldy]

I doubt being setup as the wrong type would make that much difference.

I presume you tried cutting the power to the esc, then recalibrating it with the correct motor? A lot of escs won't like a motor being swaped like you did in the vid, it will need calibrating. Also if you can change the timing to high other than the stock settings it might help.

To prove the motors good you need to check the phases are balanced with a multimeter. Check the resistance of the phase wires against eachother... They should all be pretty close... If there not, it's the motor. Also check the motor phases to earth (in this case the motor case) to see if something's shorting.

[Ellis]

Yeah we have tried all different timing and different PWM ranges, still not running right at all. They do have an effect but it's gutless regardless. Still gets hot regardless, too.

Also yes, we have re-calibrated with the turnigy several times, same behaviour.

Haven't tried the checking to earth, will do next. Looking more and more like a dud.

edit: checked, all is correct. I can't think of any other reason for this behaviour, other than the ESC and motor simply not being compatible, but there is no mention of limitations in the product description for the ESC.

[overkill]

The motor didn't seem to be turning at all to start with. If you give it a kick-start by manually turning the shaft, does it start running? That's a symptom of a bad phase I saw on one of the bots over here. It could be an internal short, which accounts for it warming up so fast. one other thing to look for is wear around where the wires enter the motor case. You might find the insulation has moved or worn through, or that some of the wires have gotten metal fatigue and snapped. That would be hard to fix but its worth knowing why the motor broke so you can avoid it in the future.

I'm with the other guys; its time for a replacement motor.