First post here, and I must say this looks like a nice community! I am looking for a motor for my project and need some help. Planning to use an Odrive and a brushless motor from hobbyking since the preffered odrive motor is sold out. The motor shall pull a wagon quite forcefully through a water tank using some GT3 belts and pulleys:
The short timing belt symbolizes a transmission ratio or gear of some sort. I did some calculations in Julia and the required motor power is seen in the next post (New users can only upload one image per post)
So this is the power needed.
If i assume a gear ratio of 1, the speed on the motor is as follows:
The torque is as folows
This is too slow for hobby motors, so I am thinking of a gear ratio of two and a Turnigy SK3 or SK8 with about 130 KV. Will they stand up to this?
And what will be the performance difference (in my project) between these two versions of the SK8
Couple of thoughts that I had:
You have your machine going from 0 to 25 revolutions per second within half a second. This much acceleration seems … excessive. I also have doubts that without careful engineering that a system made of belts could survive such a dramatic jerk. What are you ultimately trying to accomplish? How much horizontal force are you ultimately trying to impart on to your wagon and for how long? If this motion is going to be repetitive or continuous it impacts the selection of the motors as they will need to withstand repeated peak currents without overheating.
The accelleration may seem excessive and may not even be necessary, but the movement I want is slower than the liteplacer on the odrive front page, so I do not think it is outrageous.
The force on the gantry will be as follows:
As I have seen, this is well within the GT3 belt specs.
I will ofcourse give the motor and controller a break between the excursions and I will have them actively cooled
And I would like to not go into the ultimate goal at the moment. Is that OK within the open source community?
That power is well within the spec of the SK3. Make sure they’re well supported (output shaft in double shear) so the bearings don’t die on you.
If you get the torque down to about 1-2Nm you’d be set.