Moteur à courant continu
A DC motor is the motor effect harnessed for continuous rotation, and the whole trick lies in the commutator. This simulation shows the current path through the coil, the forces on each side, and the moment the split ring reverses the connection to keep the rotation going one way.
Comment utiliser cette simulation
- Adjust the current supplied to the coil
- Change the magnetic field strength
- Step through the rotation to watch the commutator act
Ce qu’il faut observer
- Forces on the two sides of the coil always point in opposite directions
- Torque is largest when the coil lies parallel to the field and zero when perpendicular
- Without the commutator the coil would simply oscillate instead of rotating
La physique derrière
Each side of the coil carries current across the magnetic field and feels a force F = BIL, and because the two sides carry current in opposite directions the forces form a couple that turns the coil. Half a turn later that couple would reverse and stop the motion, so the commutator flips the current direction at exactly that point.