As an example, if accelerometer output from a CMG reaches 0.2 g, the
CMG will be taken out of the active steering loop, to ensure zero
gimbal rates. If, in addition, the current drawn by its spin motor is
0.5 amps or greater for five minutes, the rotor will be commanded off.

So what does "commanded off" mean? I would guess that it means that
the motor stops driving it and the wheel now spins freely, gradually
slowing due to friction. At least, at a first guess that would be
less of a strain on the hardware than the other alternative which
springs to mind, which would be to try to stop the wheel as quickly as
possible.

So if we are talking about gradually slowing due to friction, how long
does it take for a CMG to stop?