Hydrostatic drive electronic control circuit - uses FET as part of circuit to keep product of speed and torque constant

摘要

A constant voltage is applied to the terminal (1). A signal, the voltage of which is proportional to the pressure in the hydraulic transmission system, is applied to the terminal (7). This signal is transmitted through the resistance (R9) and the amplifier (V2) to the gate of the FET (T1). By correct choice of the magnitudes of the resistances (R6, R7, R8) the output from the FET (T1) can be made proportional to the product of the pressure signal voltage and the speed signal voltage. This output is transmitted to the control terminal (6) and controls the speed of the drive so that it varies inversely as the torque. This ensures that the power demand on the engine remains constant.