Electronic Control of a Modulated Torque Converter

On lift-cranes, sluggish load response to operator commands using pneumatic controls prompted the development of an electro-hydraulic proportional pressure control system to engage the input clutch on a hydraulic torque converter. Continuous modulation of hundreds of horsepower was reduced to a control task no more difficult than changing the intensity of a 12-volt light bulb. Tests with systems under manual control proved so responsive that high-performance, closed-loop speed regulation was not only practical but ultimately had enough precision, for example, to adjust the phase angle of a 3600 RPM electric power generator.