Mechanics and Construction > Mechanics and Construction

What about Polulu?

<< < (2/3) > >>

Botzor:
Sounds good this. I ordered two 10:1 micro gear motor and some other stuff I need for a line follower now.  ;D

The torque from the 5:1 motor probably would have sufficed if driving it over stall current, but it felt better to run the motor at a higher speed at a current a bit lower than at stall.

Is my intuition correct? How warm do these motors get when running them at stall current?

jwatte:

--- Quote ---How warm do these motors get when running them at stall current?
--- End quote ---

Probably warm enough to overheat the motor if you do it enough. Typically, motors are not rated to run at stall current for long times.

Then again, if you solve a line following problem in 30 seconds, that might not count as "a long time" :-) Please let us know what you find!

waltr:
Not not design to have any motor running at Stall for more than a few seconds.
The best design runs the motor at about half of stall and is where the motor runs at best efficiency and maximum output power.
Here is a link about motor:
http://www.micromo.com/dc-motor-tutorials.aspx

The Motor Calculations paper is very good as is how to select a motor.

One Bot I built uses the Pololu micro-gear motors with a 100:1 ratio. Works great.
I'll guess that you will find that the 10:1 motor, unless you add additional gearing, will be too fast for a line-follower.

jwatte:

--- Quote ---The best design runs the motor at about half of stall and is where the motor runs at best efficiency and maximum output power.

--- End quote ---

Actually, it's often much less than that. Good motors are rated for "continuous current" separate from "stall current."


--- Quote ---10:1 may be too fast
--- End quote ---

That kind-of depends on how big his wheels are, and how fast he can make his sensors. If the goal is to dominate the line following competitions, that may be just the right way to do it :-)

I use the 35:1 micro metals in a Zumo treaded mini-rover, and they work fine as long as I don't solder too hotly/long to their connectors.

Botzor:
waltr: That was an informative page.

I've seen that the fastest the fastes line followers in Europe offically average around 2-3 m/s and got a peak speed slightly over that.

I don't know if it's realistic yet but I therefore aimed at a top speed of 5 m/s for a certain victory or at least a very  powerful crash  ;)

With my wheel size the 10:1 motor is reving a whooping 30 000 rpm when driving 5 m/s which must be rather extreme for a brushed motor.

However,  I dont even have a slight clue about possible mechanical losses from wheel friction etc. If those tend to eat more than a few mNm, the 10:1 was the one to go.



Navigation

[0] Message Index

[#] Next page

[*] Previous page

Go to full version