Put the motor effect on a coil and the two sides are pushed opposite ways, so it spins. The clever part is a split ring that flips the current at just the right moment, so the spin never stalls.
A d.c. motor spins a current-carrying coil in a magnetic field. The forces on opposite sides act in opposite directions and turn the coil. A split-ring commutator reverses the current every half turn so the rotation keeps going the same way.
A d.c. motor uses the motor effect: the two sides of a current-carrying coil in a magnetic field feel forces in opposite directions, which turn the coil.
The commutator keeps the coil turning the same way instead of stopping or rocking back.
Watch the forces turn the coil and the commutator flip the current each half turn.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
A d.c. motor works because of the...
The forces on the two sides of the coil are...
The part that reverses the current every half turn is the...
A d.c. motor spins faster if you...
Without it the coil would stall; with it the turning continues smoothly.
A d.c. motor needs a split-ring commutator, not slip rings. The commutator reverses the current every half turn, which keeps the coil turning the same way instead of stalling or rocking back and forth.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
What is the purpose of the split-ring commutator in a d.c. motor?
Without a commutator, after half a turn the coil would...
The two sides of the motor coil experience opposite forces because they...
The d.c. motor is mapped. Keep the chain going.