The Electrohydraulic Power Servo (EHPS) has been replaced by the VariStroke servo line.
The Electrohydraulic Power Servo (EHPS) is a fully integrated three stage servo valve designed to drive low-pressure steam turbine control
valve cylinders. The EHPS, in conjunction with a new or already installed steam valve cylinder, provides the linear actuation force to operate steam turbine control valves or valve racks. This servo can be configured to drive single or double acting actuators, and to use the system’s turbine lube oil supply, or a separate oil source (5.5–17.2 bar, 80–250 psi).