Hello Polulu Team,
I’m building an inverted pendulum that is stabilized by a reaction wheel driven by the 25D Metal Gearmotor (12 V medium-power, 34:1 gearbox, with encoder).
To design the wheel, I need to know the maximum permissible load moment of inertia that can be attached to the motor shaft without risking damage to the gearbox or motor during rapid start/stop or direction changes. Is there a maximum recommended load inertia for this motor?
Thanks in advance for your help!
Hello.
To avoid confusion, please note that our company name is Pololu, not “Polulu.”
We do not have a specific recommendation for the maximum inertia that our 25D motors can handle since that is going to depend on how quickly you want to be able to accelerate and decelerate the load. However, we do note on the product page and in the motor datasheet that to avoid damaging the gears the recommended upper limit for continuously applied loads is 4 kg⋅cm (55 oz⋅in), and the recommended upper limit for intermittently permissible torque is 8 kg⋅cm (110 oz⋅in). Also, to avoid damage to the motor windings and brushes, a general recommendation for brushed DC motor operation is 25% or less of the stall current (or extrapolated stall torque). So if you identify a maximum acceleration rate for your reaction wheel, then you can combine that with the torque recommendations to work out a value for inertia.
- Patrick
