Servo Repair / Remanufacturing

Proportional Valves
Proportional valves control flow or pressure in response to an electrical or electronic control signal. They can be infinitely positioned to control the amount, pressure and direction of fluid flow. The distinction between servovalves and proportional valves is blurred but, in general, servovalves provide a higher degree of closed-loop control. Both types of valve are used for control in pneumatics, hydraulics, gas, steam, water transport, and other specialized applications. The performance of proportional valves falls in the wide spectrum between on/off solenoid valves and electrohydraulic servovalves. The valves are termed proportional because their output flow is not exactly linear in relation to the input current. Despite their nonlinear response, these valves are an inexpensive way to control position, velocity, or force on equipment requiring high-speed response at high flow rates.

Servo Motors
A DC servomotor has an output shaft that can be positioned by sending a coded signal to the motor. As the input to the motor changes, the angular position of the output shaft changes as well. Servomotors are generally small and powerful for their size, and easy to control. Common types of DC servomotors include brushless or gearmotor types.

AC servomotors are typically permanent magnet synchronous motors that can often have low torque-to-inertia ratios for high acceleration ratings. An AC servomotor has an output shaft that can be positioned by sending a coded signal to the motor. As the input to the motor changes, the angular position of the output shaft changes as well. Servomotors are generally small and powerful for their size, and easy to control. Common forms of AC servomotors include induction and gearmotor types.

Servo Valves
Servovalves (or servo valves) provide closed loop flow or pressure response to an electrical or electronic control signal. They can be infinitely positioned to control the amount, pressure and direction of fluid flow. The distinction between servovalves and proportional valves is inconsistently defined, but in general, servovalves provide a higher degree of closed-loop control. Both types of valve are used for control in pneumatics, hydraulics, gas, steam, water transport, and other specialized applications. In a conventional open-loop force control system, servovalves output pressure, which is applied to the hydraulic piston that drives the load. The controlled pressure may be the differential between the two sides of the load actuator or it may be the pressure in a single line connected to one side of the load actuator.