II Explanation of the Electric Motor Demonstrated in Class

I Rotor or armature (the rotating piece of the motor) Explanation of the Electric Motor Demonstrated in Class I

τ I I II B ext Coils (or bar magnets) are used to create the external magnetic field B coil Follow the wires and find this direction of current at this instant Which induces this B-field Explanation of the Electric Motor Demonstrated in Class To align the B-fields, a CW torque is created. In this position, the torque is maximum Rotor or armature (the rotating piece of the motor)

τ I I II B ext The rotor rotates B coil Explanation of the Electric Motor Demonstrated in Class In this position, the angle between B coil and B ext has decreased, so the torque has decreased

τ =0 B coil II B ext B coil The rotor continues to rotate In this position, the B-fields are aligned and the torque is zero Explanation of the Electric Motor Demonstrated in Class

τ I I B coil II B ext Momentum carries the rotor further around Follow the wires in this position and find that the current in the coils has changed direction Inducing a B-field in this direction And so the torque continues to be clockwise. Explanation of the Electric Motor Demonstrated in Class

τ I I II B ext B coil The rotor rotates to this position, which is 180º from where it started. Since the current and B coil have switched directions, it is essentially the same configuration as it was at the start. Explanation of the Electric Motor Demonstrated in Class And so, the process repeats…