Here are a few possibilities:
* Helicopter rotors: These spin horizontally, usually counter-clockwise when viewed from below. This is to counteract the torque created by the spinning blades, which would otherwise make the helicopter spin in the opposite direction.
* Turbine rotors: These spin vertically, usually clockwise when viewed from above.
* Car brake rotors: These spin horizontally with the wheels, so the direction depends on which way the car is driving.
* Electric motor rotors: The direction of rotation depends on the motor design and the direction of the current flow.
Could you please give me more context? What kind of rotor are you interested in? I'd be happy to give you a more specific answer!
