At a current of 20 A, a force of 1.0 N acts on the wire of the armature winding of the electric motor.

At a current of 20 A, a force of 1.0 N acts on the wire of the armature winding of the electric motor. Determine the magnetic induction if the length of the wire is 0.2 m.

Data: I (current in the armature winding) = 20 A; Fa (Ampere force) = 1 N; l (armature winding wire length) = 0.2 m; the wire of the armature winding of the electric motor is located perpendicular to the magnetic induction vector (α = 90º and sinα = 1).

We calculate the magnetic induction using Ampere’s law: Fa = I * B * l * sinα, whence B = Fa / (I * l).

Calculation of magnetic induction: B = 1 / (20 * 0.2) = 0.25 T.

Answer: The magnetic induction is 0.25 T.