Originally Posted by BeastFromDaEast
that is yea , lol jokes on him/her
no it isn't.
I think everyone agrees that there is nothing wrong with your car. They are not meant to be driven extremely slow. The noise (high pitched) you hear is the motor acting like a speaker. It is resonating back and forth extremely fast with only such a small amount of throttle. You are hearing the frequency of the speed control.
They work by switching the power on and off really fast. The frequency stays the same but the ammount of time the on pulse is "on" determines your speed. Shorter pulses are slow speed, longer on pulses result in more speed.
The armature in the motor is unable to overcome the strength of the magnets when you apply only a very small ammount of throttle. so instead of spinning, it rings back and forth in the motor can; producing the noise you hear.
See, when the armature is moved in the magnetic field of the magnets,(by your hand or by pushing the car) the magnets produce a current in the coils that is opposite the magnetic field of the magnets. That current in the coils produces an opposing magnetic field which causes resistance to rotation, so the armature wants to basically stop. That is the "notchy" feel you are feeling when you try and slowly push the car, or rotate the motor with your fingers.
Who is the joke on again?