I have recently purchased the POLOLU 499:1 Metal Gearmotor 25Dx58L mm LP 6V DC motor, which I use in combination with the TB9051FTG motor driver. I have a problem that when I try to rotate the motor by applying an external force to it, it doesn’t rotate. In my particular application, this is an important aspect, and it is also important that the motor can ‘break’ when needed, hence why I chose this driver. I do not think that the issue lies with the driver, because the issue persists even when the driver is not connected to the motor, (both of the pins are floating). Please help, since I am not very experienced in this field.
Our gearmotors are not designed to be backdriven like that, and we have not characterized the torques required to do so. Additionally, trying to backdrive gearmotors with high gear ratios (like yours) has the potential to damage the gearbox.
For an application where you do need to move the load by hand when the motor is turned off, you might consider adding a clutch mechanism, though we do not have any specific recommendations for that. Alternatively, you might consider switching to a stepper motor since it is usually possible to command stepper motor drivers to de-energize the coils so that the only resistance from the motor will be the detent torque, which tends to be very low.
