[protoserge]

The RS series motors need active cooling to keep the enamel on the commutator shaft from melting. This is achieved in stock form by an internal fan and air ducts at the front and rear of the housing. The RS series motors are intended for power tools and R/C cars where they have plenty of air movement and are typically driven in one direction for a continuous period of time (not fast forward-reverse motion like the FRC robot).

The CIMs and MiniCIMs have a higher thermal mass to dissipate the heat and typically use the gearbox as a heatsink. The large mating surface area helps conductive heat transfer and the overall larger system mass provides more heat capacity. During extended runs, you will likely notice the housing of both the gearbox and motor are warm, but not necessarily hot, unless there is high friction due to under/over-greasing of the transmission or improper assembly or other motor failure mode.

I do not recommend using an RS motor for a critical, high load (high current) application such as the drivetrain.