# Phase voltage

Voltage across the phase winding.

In Emetor, the phase voltage is calculated based on the dq-quantities of current and flux linkage as follows: $$U = \sqrt{ U_d^2 + U_q^2 }$$ $$U_d = R_{ph} \cdot I_d - \omega \left( \Psi _q + L_{end} \cdot I_q \right)$$ $$U_q = R_{ph} \cdot I_q + \omega \left( \Psi _d + L_{end} \cdot I_d \right)$$ where $R_{ph}$ is the phase resistance, $L_{end}$ is the phase end-winding leakage inductance, $I$ is the phase current, $\Psi$ is the flux linkage, and $\omega$ is the angular electric speed $(=2\pi f)$.