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Electric motor
Intermediate
Converts electrical energy to rotation.
A current loop in a magnetic field with a commutator that reverses current every half turn gives continuous rotation. Torque is largest when the loop is parallel to the field.
Brushless motors use electronics instead.
Spinning generates back EMF.
In more detail
An electric motor converts electrical energy into rotational kinetic energy using torques on current-carrying coils in magnetic fields. A commutator reverses the current so the torque keeps rotating in the same direction.
Real-world uses
- Fans, washing machines and electric cars use motors.
- Drills and hard drives use small motors.
- Electric fans, washing machines and electric cars all use motors that convert electrical energy into rotation.
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Frequently asked questions
Why does the commutator matter?
It reverses the current every half turn, so the torque does not reverse and stop the motor.
Does a motor produce electricity?
When it turns, it also produces back emf, which opposes the input voltage.
What is the basic principle of a motor?
A current-carrying coil in a magnetic field experiences a torque that makes it rotate.
Related topics in Magnetism & Induction
Definition of the ampere · Torque on a current loop · Moving coil galvanometer · Biot–Savart law · Field of a long straight wire · Field at centre of a loop