Speed, Acceleration, and Load Control Solid-State System

An all solid-state system for controlling the acceleration, speed, and load of central station steam turbines or the acceleration and speed of paper machine drive turbines is described. This new high-performance system eliminates the moving parts and gives lower drift and better reliability than previous solutions which used a motor driven potentiometer or an integrator operational amplifier. A desired speed is preset in a digital register and the speed of the turbine is brought toward this desired value at a selected rate. A control is provided to hold any present operating speed indefinitely. For central station steam turbines, the same equipment is used for load control after synchronization. Since high precision is required, the system is digital and drives a simple digital to analog converter to provide the analog output signal. The equipment may be operated from a remote panel or by a digital computer.