Actuators & Their Applications

PREPARED & PRESENTED BY:

ENGR. FAHAD KHAN

What is an actuator. Actuator is an output device but it does not always provide output directly to the

user.

It can change some physical value in response to a signal which is actually sent by sensor and processed by processor and finally fed to the actuator to perform the desired tasks.

Actuators and sensors are paired up together in control systems.

Control system or feedback control system is a system in which out is continuously matched with input to get the desired values at output.

In next slides few examples of actuators are discussed.

Controlling an Irrigation System Consider a program for controlling an irrigation system which can

turn on the water supply when the soil gets too dry.

The control program can generate an electric output signal but this signal cannot open the water supply valve directly. The output signal must be sent to an actuator that can operate the valve.

A suitable actuator for an irrigation valve is a motor or an electromagnet called as a solenoid. This is often built into the valve.

A solenoid acts like a magnet when current is passed through it

Controlling Lights in a Greenhouse Automated systems use light bulbs to provide artificial lights in a

greenhouse for forcing the growth of plant. An actuator can be used as a relay to control the lights and turn on and turn off these lights as per the predefined timing and can control their intensity as well according to the need.

Light Bulbs & LEDs as Actuator It is really amazing to know that we can also use light bulbs and

LED (Light Emitting Diode) as actuators.

These bulbs or LEDs can be used as indicators in various systems to show the status of an equipment such as blinking LED as warning of fault in an equipment.

Electric Heater as Actuator An electric heater is an actuator that supplies heat.

Automated systems use electric heaters for industrial processes and for heating buildings and greenhouses as well.

Heat pump can also be used as an actuator that provides cooling for food stored in refrigerators and air conditioning systems in building.

Relay as Actuator A computer needs an extra actuator to switch on and off the

electricity supply to the main actuator such as heater.

This kind of electrical-switching actuator is called a relay or a contactor.

Temperature Sensor

Temperature Control

Computer System

Relay or Contractor

Heater

Main ElectricityControl

Electric Motor as Actuator An electric motor is an actuator which provides rotatory motion

or linear movement.

Automated systems use motors to rotate microwave oven turntables, washing machine drums, hard disk drives in computers, optical disks in computers and CD and DVD players.

Electric motor is also used in feed rollers and drums in printers, fans in heating, ventilating and air conditioning systems, drills, lathe spindles in industrial robots, known as computer controlled machine (CNC).

Motorised Pump as Actuator A motorised pump forms as actuator that moves gases or liquids.

Automated systems use pumps to move water in dishwashers, washing machines, water filled heating systems, refrigerants in heat pumps, gases and liquids in industrial processes.

An automatic blood pressure monitor uses an air pump to inflate its cuff.

A motorized fan is a low pressure pump for gases.

Buzzer as Actuator A buzzer is an audio signaling device that makes a rasping

sound.

Automated systems use buzzers or similar actuators such as bells, beepers or sirens to indicate an event to the user.

For example, a beeper can make a sound when a microwave oven finishes heating.

A siren can sound when a fire alarm detects a fire.

Thank You