Brushless motors in the lego world - general topic

[gyenesvi]

I wonder if the fact that there has not been melting problems with the Buwizz 3 and Buwizz motors is related to that the Buwizz had shutdown problems, meaning that it shut down before melting could have happened :) And what will happen now that the shutdown problem has been fixed. Though the problem has been fixed by limiting the power when the current goes high, so hopefully that still prevents melting as well..

[Lixander]

18 hours ago, gyenesvi said:

I wonder if the fact that there has not been melting problems with the Buwizz 3 and Buwizz motors is related to that the Buwizz had shutdown problems, meaning that it shut down before melting could have happened :) And what will happen now that the shutdown problem has been fixed. Though the problem has been fixed by limiting the power when the current goes high, so hopefully that still prevents melting as well..

I see. Still curious though (but I dont know if I will get a BuWizz set-up in my hands :/ )

Edited September 10, 2023 by Lixander

[2GodBDGlory]

On 8/29/2023 at 5:51 PM, 2GodBDGlory said:

I'm not sure if this is relevant here, but I'm currently running two AliExpress buggy motors off of a custom 3S Lithium battery in a WIP 6x6, and haven't had any problems yet (and haven't in previous models with this drivetrain, like my latest Toyota Land Cruiser 70), so they do seem to hold up alright, in my experience!

Well, about that...
I was testing out that 6x6 WIP yesterday afternoon, and sure enough, one of my buggy motors started smoking, and no longer works...

It was only after running under significant load, often to stall, for a decent while, though, so more careful usage seems to work alright?

[ITSDEEKAY]

On 9/10/2023 at 11:18 AM, 2GodBDGlory said:

Well, about that...
I was testing out that 6x6 WIP yesterday afternoon, and sure enough, one of my buggy motors started smoking, and no longer works...

It was only after running under significant load, often to stall, for a decent while, though, so more careful usage seems to work alright?

That's unfortunate. I came to accept that a lot of the motors and battery modifications are made in the Europe and enthusiasts such as buwizz. I found a modified RC brick control that allows to run 2 buggy motors with no issues from an Russian lego enthusiast. Again all of these are unobtainable for me since I live in the US. I'm happy enough with the power of 3s lipo batteries gives to my motors safely without burning up.

[glowytheglowbug]

i have been wanting to create a brushless crawler/buggy to go off-roading for a while
from what i can tell it probably would be either 1/8th scale or 1/10th scale and I need a sensored brushless motor

an esc for the brushless motor

a receiver and controller for a servo and esc

and battery.

does anyone have any suggestions? I don't want to use too much gearing if possible and have a single motor 

[Daniel-99]

8 hours ago, glowytheglowbug said:

i have been wanting to create a brushless crawler/buggy to go off-roading for a while
from what i can tell it probably would be either 1/8th scale or 1/10th scale and I need a sensored brushless motor

an esc for the brushless motor

a receiver and controller for a servo and esc

and battery.

does anyone have any suggestions? I don't want to use too much gearing if possible and have a single motor 

Well, I would not suggest you any brand or so, but I want to note, that with a BR motor it would be a hard to avoid extra-gearing. BR motor has a high RPM, so you will have to decrease it triply \ quadriply... One way to go here is to use planetary hubs, or to use an RC brush motor instead which will work perfectly for crawlers (with brush-motor you will need a different ESC as well).

[glowytheglowbug]

On 9/29/2023 at 4:51 PM, Daniel-99 said:

Well, I would not suggest you any brand or so, but I want to note, that with a BR motor it would be a hard to avoid extra-gearing. BR motor has a high RPM, so you will have to decrease it triply \ quadriply... One way to go here is to use planetary hubs, or to use an RC brush motor instead which will work perfectly for crawlers (with brush-motor you will need a different ESC as well).

ooh thanks, i dont mind gearing down, i can use metal axles, metal gears/pulleys, geared wheel hubs... etc i dont mind super high rpm so long as i have good control of the torque and good speed to go zooming across flatter terrain

[Daniel-99]

4 hours ago, glowytheglowbug said:

ooh thanks, i dont mind gearing down, i can use metal axles, metal gears/pulleys, geared wheel hubs... etc i dont mind super high rpm so long as i have good control of the torque and good speed to go zooming across flatter terrain

I see! We'll be looking forward to your BR mocs. And welcome to the Brushless Lego club ;-)

[Lixander]

On 9/29/2023 at 3:12 AM, glowytheglowbug said:

i have been wanting to create a brushless crawler/buggy to go off-roading for a while
from what i can tell it probably would be either 1/8th scale or 1/10th scale and I need a sensored brushless motor

an esc for the brushless motor

a receiver and controller for a servo and esc

and battery.

does anyone have any suggestions? I don't want to use too much gearing if possible and have a single motor 

How are you going to put the RC motor in the Lego model..........with an adapter or?

[Ryokeen]

Motors with 3.17mm shaft can use a mod 1 pinion gear with 12 tooths and those match with lego gears perfectly. So you can start with a 12:20 reduction or 12:36.
540 motors and most rc motors are screwed to an chassis with m3 screws which in turn fit trough pinholes but the head of the screw won't. Think further back is a youtube vid where one showed how a 540 brushed motor can be attached that way.
And from my own experience i can say it works quite well, if you support the motor a bit at the back aswell.

[Lixander]

11 hours ago, Ryokeen said:

Motors with 3.17mm shaft can use a mod 1 pinion gear with 12 tooths and those match with lego gears perfectly. So you can start with a 12:20 reduction or 12:36.
540 motors and most rc motors are screwed to an chassis with m3 screws which in turn fit trough pinholes but the head of the screw won't. Think further back is a youtube vid where one showed how a 540 brushed motor can be attached that way.
And from my own experience i can say it works quite well, if you support the motor a bit at the back aswell.

Thanks for the useful informations!

[glowytheglowbug]

On 10/24/2023 at 3:23 PM, Lixander said:

How are you going to put the RC motor in the Lego model..........with an adapter or?

probably with something like this? some kind of adapter people sell 

23 hours ago, Ryokeen said:

Motors with 3.17mm shaft can use a mod 1 pinion gear with 12 tooths and those match with lego gears perfectly. So you can start with a 12:20 reduction or 12:36.
540 motors and most rc motors are screwed to an chassis with m3 screws which in turn fit trough pinholes but the head of the screw won't. Think further back is a youtube vid where one showed how a 540 brushed motor can be attached that way.
And from my own experience i can say it works quite well, if you support the motor a bit at the back aswell.

got any suggestions for brands of motors? (1/10th or 1/8th scale)

[Ryokeen]

3 hours ago, glowytheglowbug said:

got any suggestions for brands of motors? (1/10th or 1/8th scale)

Atm not rly :D have only started on my journey. Currently i use an absima 80t 540 brushed motor(around 20€) as i rather have more torque than rpm and first wanted to use it for a crawler or in a bigger tank. But with a 4 speed gearbox it's still fast enough in my delorean :D
Tomorrow an Razer ten 3652 3250 KV should arrive as a somewhat cheap brushless testing motor.

For me the criterias where, how fast the motor turns, as you need more gearing and ballbearings for high rpm. Price ofc ;) and torque. Finding proper torque values can be a pain.
The motor i use has no problem moving my current model even in 3rd gear(think 7:1 downgear including differential, so around 720rpm) from a halt. And than thing weights 3-4kg :D

[Lixander]

On 10/26/2023 at 3:19 AM, glowytheglowbug said:

probably with something like this? some kind of adapter people sell 

Interesting........do you know where I can find it?

[janssnet]

Great subject folks!

In case you're looking for (more) inspiration how to mount BLDC motors to LEGO, please find a few additional suggestions hereunder.

 

‎LEGO BLDC.‎001 

‎LEGO BLDC.‎002 

‎LEGO BLDC.‎003 

‎LEGO BLDC.‎004 

 

 

Edited October 27, 2023 by janssnet

[Lixander]

Also, I found some adapter-frames and the axle adapter.

https://cults3d.com/en/3d-model/tool/540-motor-mount-for-lego-technic

https://cults3d.com/en/3d-model/gadget/540-motor-to-lego-axle-adapter

 

[glowytheglowbug]

On 10/27/2023 at 3:59 PM, Lixander said:

Interesting........do you know where I can find it?

i found that picture in an online singapore shop i think google searching "rc motor to lego axle adapter" works

[Lixander]

13 hours ago, glowytheglowbug said:

i found that picture in an online singapore shop i think google searching "rc motor to lego axle adapter" works

Thanks a lot!

 

[Krzychups]

Hello,

@Daniel-99 can you show me your custom wheel hubs (the joints connections)? I want to make something like those. 

[Daniel-99]

18 hours ago, Krzychups said:

Hello,

@Daniel-99 can you show me your custom wheel hubs (the joints connections)? I want to make something like those. 

Hi! 

Each hub consists of three parts. 

• main body with glued metal bearing
• metal axle with a stopper (modified U-joint if the pivot is needed)
• 12 mm hex

The Idea here is the following. the "stopper" on the metal axle is a bit wider than the inner diameter of the metal bearing, so it helps to hold the wheel. The modified U-joint is somewhat tricky to make. You have to make an inner threading in a metal U-joint which is perfectly aligned with the U-joint output. The body of the hub could be made in different forms, depending on your needs.

 

[janssnet]

Hi folks,

Thanks for keeping this thread alive. Great content.

In case you're looking for a solid way to mount your LEGO gear to a brushless motor with a 3mm or 3.17mm shaft, have a look here.

https://youtube.com/shorts/jh-xOvj5AE4

 

Edited December 4, 2023 by janssnet

[gyenesvi]

3 hours ago, janssnet said:

In case you're looking for a solid way to mount your LEGO gear to a brushless motor with a 3mm or 3.17mm shaft, have a look here.

Interesting solution, though wonder why not do it with a longer pin to be able to fix it at the other end of the pinion gear as well, i would assume that such a powerful thing needs to be fixed properly from both sides. Would it work with a 3L axle-pin? (they have differing inner diameters)

[Lixander]

Also, here are the .dat files for a 540 size RC motor and an RC axle adaptor. They need to be edited in the Studio Designer, to put the connections. https://bricksafe.com/pages/Lixander_A./miscellaneous/rc-adaptors

I made the conversion of the 3D files with the help of this program https://github.com/Nexusnui/stl-to-dat-improved 

He also made a tutorial.

The original 3D files: 
https://cults3d.com/en/3d-model/tool/540-motor-mount-for-lego-technic 
https://cults3d.com/en/3d-model/gadget/540-motor-to-lego-axle-adapter

 

 

Edited December 5, 2023 by Lixander

[janssnet]

On 12/4/2023 at 10:38 PM, gyenesvi said:

Interesting solution, though wonder why not do it with a longer pin to be able to fix it at the other end of the pinion gear as well, i would assume that such a powerful thing needs to be fixed properly from both sides. Would it work with a 3L axle-pin? (they have differing inner diameters)

Sure, you could use 18651 (3L axle pin), but you would (indeed) have to drill a round 3mm hole in it first. 

There is however no real need to fix it at the other end. In fact it would only increase drag. Please note, the motor shaft goes all the way through the motor and the 2L axle pin is strong enough to give serious torque. 

Have a look here ...

 

[gyenesvi]

3 hours ago, janssnet said:

Sure, you could use 18651 (3L axle pin), but you would (indeed) have to drill a round 3mm hole in it first. 

There is however no real need to fix it at the other end. In fact it would only increase drag. Please note, the motor shaft goes all the way through the motor and the 2L axle pin is strong enough to give serious torque. 

I can believe that it works in this application, but I think it's due to the circumstances: it's a light weight vehicle, there's not much down gearing after the motor, and the tires don't have much traction (it will never get stalled since it can easily spin the tires under itself). If it was a bigger/heavier build, 4-wheel drive, with large grippy tires, then I could easily imagine that gear connection skipping. But I could be wrong, just thinking that otherwise such gear meshes would work in other MOCs as well, but that's not the case (they typically have to be braced from both sides). The only thing I can think of why this may work in a more general setting as well is that this connection is at the very beginning of the drive-train, and if all the down-gearing is after this, then there may not be much stress on this one.

Do you have some links to the motor/ESC you used? Are the motor mount holes 16mm apart? And what's that connector trick you use for the motor cables? Looks interesting!