I am looking at getting 2 of the BCM 60:1 Gear Motor Offset Output motors ( pololu.com/catalog/product/984 )
with the mentioned BCM Wheels ( pololu.com/catalog/product/988 ) that come separately. What is the maximum weight that they can pull/push? My total weight on this platform will be 8 to 10lbs. I like these motors because they say I can get a no load speed of 180 RPM. I know I will not be moving that fast with 8 to 10lbs but I hope to be moving quick enough. I will be running at 6 to 8 volts.
Also do I have to be concerned with that stall current? I will be using this platform to roll around a small track to demonstrate a concept. Any and all comments are appreciated, thanks?
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The BCM motors are listed at a stall torque of 11 oz in, and the wheels have a radius of a little over an inch. That means the stall force from each motor will be about 10 oz. Two of the motors will give you a total force of about 20 oz, which around 10% of the weight of your robot. That sounds like it will be quite underpowered, and it will probably stall if it hits a bit of friction or the slightest bump.
You definitely have to be concerned with stall current, since that will usually be reached when you first start driving or if your robot bumps into something. So you need to make sure that your motor driver can handle that and at the very least not break!
Thanks Paul, that was what I was afraid of. I will need to go bigger with the motors. Not sure what would be economical as an upgrade for my desired weight. I liked the way the motors and wheels went together so easily.
Some of the bigger metal gearmotors we have should do the job, but they do cost more. Those BCM wheels aren’t all that great for a 10-pound robot, either. With the aluminum hubs we sell, it shouldn’t be that difficult to mount some nicer wheels to the motors. Something like inline skate or scooter wheels might be nice.