The initial automotive application from the lock-up basic principle was Packard's Ultramatic transmission, released in 1949, which locked up the converter at cruising speeds, unlocking in the event the throttle was floored for rapid acceleration or given that the car slowed. All these electric power conversions arrive with some losses. https://rowanedayv.bloggazza.com/33004204/the-torque-converter-clutch-diaries