I intend on building a small robot with a DC motor that operates with voltage of 3V-6V. The website provides the no-load rpm, no-load current, stall current and torque all when it is at 3V. My first question is how can i determine this at 6V.

My second question is that from there, how do i determine the load on the motor in order to calculate if it is too much. Along with that i also need to know how to get the rpm at that load to calculate efficiency.

The motor is a TAMIYA 70167. Thanks in advance.

• Please make sure to provide the correct data: TAMIYA 70167 is a motor plus gear box. The motor itself is (probably) a Mabuchi motor FA-130 #18100. Mar 16, 2019 at 11:59

The load you need to calculate is what the motor needs to overcome.

This will be based on what it has to drive ie force * distance or gears : rack and pinion or a pump to produce a hydraulic force etc

If the motor is ok to operate at 6 volts, the torque capability will be about the same as at 3 volts. To get the operating RPM, you construct a motor torque vs. speed curve for 6 volts and load steady-state torque vs speed requirement curve. The operating point is the intersection of the two curves. To do that you need to consider load and drive train friction and aerodynamic drag plus work done in operating the load. Any torque capacity that is left over will be available to accelerate the load inertia.

I would not use a Mabuchi motor FA-130 #18100 on 6V. It is rated to work on 1.5V to 3V. The website https://www.pololu.com/product/118 warns not to stall the motor. When driving it on 6V, it will burn twice as fast when stalled.

Why not use their recommendation:

Note that you can replace the motor in this kit with a lower-current, higher-voltage motor if you want to use this gearbox ...

That motor is rated for 6V.

You can drive a DC motor with more than the rated voltage. But you need to know what your doing to make sure not to burn the windings of the motor.