My first robot(hopefully)

[programCurtis]

I'm looking at the banebots website and after reading what you said about the current I was wondering if the BB-12-45 ESC ( http://banebots.com/pc/ELECTRONICS/BB-1245 ) will be able to provide enough current for the RS550 Motor - 12V?

I decided that I may as well go all out on this project. I am also interested in all the aspects of this project including the design, construction, and programing.

[RyanCahoon]

Originally Posted by programCurtis

I'm looking at the banebots website and after reading what you said about the current I was wondering if the BB-12-45 ESC ( http://banebots.com/pc/ELECTRONICS/BB-1245 ) will be able to provide enough current for the RS550 Motor - 12V?

Nice catch, I had misread it as 45A continuous. The BB-12-45 could something like the RS-395 and probably the RS-540 if you were careful, but the RS-550 is going to be a bit much for it in most cases.

As explanation: the peak efficiency, no load, and stall currents they list on the page will give you a basic idea of the current requirements for the motor, and describe three notable operating conditions for the motor, but to get a better sense for specific applications, you can make use of the motor curve that FIRST posted for the RS-550. Figure out how much torque your motor will need to output in the worst case (if your robot is going up hills, pushing things, etc) - maybe look at some of the resources posted here about gearing choice to make sure you have the right gear reduction for your application and make sure to account for efficiency losses in the gearbox - find this torque on the X-axis, and then find the corresponding point on the current curve. You'll also want to add some safety margin, and then this will give you a good idea of your needed continuous current; note that your motor will draw more than this at some points, but this is where the peak current rating for the motor controller comes in, as long as you have a safety margin so that you don't jump into that region too often. If you work through this, I expect you'll get a higher number than 12A for your continuous current. When working with these kinds of currents, you may want to consider designing in some sort of fuse or circuit breaker as well, to prevent horribly catastrophic failure.

Just a quick look around gave me this controller from robot Robot Marketplace that support 40A continuous / 60A peak for about the same price that might be an option, without looking too much into the details.

--Ryan

*I think I may have glossed over some details in the interest of brevity, always feel free to ask if you have any questions.

[MrForbes]

If you're going to get into robot pushing matches, then you need a more powerful motor controller. But for just driving around, the 12 amp controller should be fine....as long as you don't have a long skid steer robot. Using two drive wheels, and caster(s) to keep it balanced, should make it so you don't work the motors and speed controllers very hard.

Those little motors will smoke if you try to work them too hard. Having a speed controller that will cut off like the BB ones will, could be a good thing.