Running Torque of 131:1 Metal Gearmotor 37 D

Hi,

It is my request that you please list the the running torque of 131:1 37D motors (pololu.com/catalog/product/1447). The website only lists the stall torque, but the motor cannot provide stall torque for more than a few seconds without burning up. How can a prospective buyer estimate the running torque since there is no direct relation between stall and running torque. Also the difference between stall and running torque can be drastic for high gear reduction motors.

Some manufactures even provide graphs showing speed, torque, current, power output, efficiency. If you could provide this information, it would be super helpful.

Without these ratings, it becomes difficult to fully appreciate the power that these motors can provide. And due to the guessing involved, one may significantly underestimate the motor to be on the safer side.

Hello.

I am not sure what you mean by running torque, but we already have all of the data we have on these motors on their web pages. All of the various things you can do with the motor will have a tradeoff with the motor life, and unfortunately, we do not have that life rated at any operating point. I would treat around 25% of the stall current as a guideline for the upper limit for good operation, and since torque scales with current, the torque would be around 60 oz. in. at that point for the motor you are talking about.

By the way, the graphs you are talking about are pretty easy to approximate from the data points we provide: torque will go from 0 at the no-load current to the stall torque at the stall current in a straight line, and speed will go from no load speed to 0 over the same range, also in a straight line. You can multiply those two lines to get power out, and then divide that by power in (which is the current times the voltage you’re running at) to get the efficiency.

- Jan