S (stall stage): In this particular place the turbine speed is zero plus the impeller is rotating; the effectiveness from the stall level is minimal, about 50%, which implies that half of the power coming with the motor is shed as a result of friction and dissipated as warmth; at https://torque-converter-clutch76418.blogolize.com/facts-about-torque-converter-clutch-revealed-73034284