AZIONAMENTI PER MOTORI A CC

Based on the fragmented text and equations provided in your input, here is a structured reconstruction of the lecture notes regarding **Electromagnetic Induction in Electric Machines** (specifically focusing on forces, flux linkages, and induced EMF). The content appears to be from a course by **Dr. N. Salvatore** titled **"Corso di Azionamenti elettrici"** (Course on Electric Drives). --- ### 1. Fundamental Forces (Forces in a Conductor) The text describes the forces acting on a conductor carrying current within a magnetic field. #### A. Lorentz Force (Electromagnetic Force) When a conductor of length $l$ carries a current $i$ and is placed in a magnetic flux density $B$, it experiences a mechanical force ($F$). * **Formula:** $$ \vec{F} = i (\vec{l} \times \vec{B}) $$ Or in scalar form (assuming perpendicular vectors): $$ F = B \cdot l \cdot i $$ * **Variables:** * $F$: Mechanical force [N] * $i$: Current [A] * $l$: Length of the conductor inside the field [m] * $B$: Magnetic flux density [T] #### B. Force on a Moving Conductor (Motional EMF context) If the conductor moves with velocity $v$ perpendicular to the magnetic field $B$, an electromotive force (EMF) is induced, or conversely, if a force is applied to move it, work is done against the electromagnetic reaction. * **Force expression involving velocity:** $$ F = B \cdot l \cdot v $$ *(Note: In the text fragments, this often relates to the back-EMF concept where $e = Blv$, and the force required to maintain motion relates to power).* --- ### 2. Electromagnetic Induction (Faraday's Law) The text explains how a voltage is induced in a conductor moving through a magnetic field. #### A. Induced EMF ($e$ or $Fl$) When a conductor of length $l$ moves with velocity $v$ perpendicular to a magnetic field $B$, the induced electromotive force (EMF) is: * **Formula:** $$ e = B \cdot l \cdot v $$ * **Derivation logic from text:** * Work done ($W$) by the force moving the conductor. * Power ($P$) = Force $\times$ Velocity. * This leads to the definition of induced voltage: $e = Blv$. #### B.