Valves: Electric and Hydraulic Actuators

Describe the basic operation of a solenoid actuator. Describe the basic operation of a motor-operated actuator. Describe the function of torque switches. Describe the function of limit switches. Describe the operation of a single-acting spring-return hydraulic actuator. Describe the basic operation of a double-acting hydraulic actuator. Describe the function of a pilot valve. Describe some ways to identify actuator problems.