English: Diagram explaining the relationship between the variables in a power equation for a Synchronous Motor. (The related equation for Mechanical power developed in a synchronous motor:

${\displaystyle P_{mech}={\frac {-E}{Z_{s}}}[cos{\theta }(E-Vcos{\delta })-sin{\theta }Vsin{\delta }]}$

${\displaystyle P_{mech}={\frac {EV}{Z_{s}}}(cos{\delta }cos{\theta }+sin{\theta }sin{\delta })-{\frac {E^{2}}{Z_{s}}}cos{\theta }={\frac {EV}{Z_{s}}}cos(\theta -\delta )-{\frac {E^{2}}{Z_{s}}}cos{\theta }}$)