Unit V : Electrical Actuators, Electron-Mechanical Actuators ● ● ● ● Electrical-Actuation system: Selection criteria and specifications of stepper motors, solenoid valves,relays (Solid State relays and Electromechanical relays). Selection Criterion of control valve, Single acting and Double acting Cylinders. Electro-Pneumatic: Pneumatic Motors, Valves: Electro Hydraulic: 3/2 Valves, 4/2 Valves, 5/3 Valves Cables: Power cable and Signal cables
Electrical-Actuation system Actuator is a device which is used to actuate a process. Actuate is to operate the process. 1. Switching devices – mechanical switches, eg. relay and solid state switches, eg diodes, thyristors and transistors app – switch on or off electrical devices 2. Solenoid – type devices used to actuate valves of hydraulic and pneumatic systems. (flow control) 3.Drive systems – DC motor, AC motor and stepper motor.
Electronics specification and abbreviation Expansion of abbreviation British mains wiring name Description One-way A simple on-off switch: The two terminals are either connected together or disconnected from each other. An example is a light switch. Two-way A simple changeover switch: C (COM, Common) is connected to L1 or to L2. Mechanical switches SPST Single pole, single throw SPDT Single pole, double throw SPCO Single pole, centre off switches with a stable off position in the centre DPST Double pole, single throw Equivalent to two SPST switches controlled by a single mechanism DPDT Double pole, double throw Equivalent to two SPDT switches controlled by a single mechanism. DPCO Double pole changeover or Double pole, centre off Equivalent to DPDT. Some suppliers use DPCO for switches with a stable off position in the centre Double pole Symbol
Drive systems ● ● ● DC motor AC motor Stepper motor