1. At the end of this chapter we should able to: •Identify the main function of a solenoid. •Identify the application of solenoid. •Describe the application of solenoid with operating valves. •Draw the symbol of a solenoid with a standard symbol. •Draw a control circuit showing the energizing of a solenoid through the closing of relay contact, using acontrol relay, two push button switches and a solenoid.
2. Solenoid is an electromechanical deviceElectrical energy is used to magneticallycause mechanical movement
3. Single Solenoid Spring Return Valve Operating the START push-button switch close the circuit to the coil of relay ICR. The coil is now energized. Relay contact 1CR-1 then closes, interlocking around the START push-button switch. Contact 1CR-2 closes, energizing solenoid A. The circuit can be de-energized by operating the REVERSE push-button switch. 1 CR-1 START REV 1 CR 1 3 4 2 1 CR-2 SOL A 1 5 2
4. Single Solenoid Spring Return Valve Time-delay relay is added. Operating the START push button switch closes the circuit to the coil of relay 1 CR. The coil is now energized. Contact 1 CR-1 closes, interlocking around the START push button switch. Contact 1CR-2 closes, energizing solenoid 1A. Contact 1CR-3 closes, energizing the coil of timing relay 1TR. After a time delay, as set on the timing relay, the timing constant contact closes, energizing solenoid 1B. The circuit can be de-energized by operating the REVERSE push button switch.
5. Applied in many electrical activated devices such as Valves Locks Punches Marking machines
6. Common Rotary Solenoid Circuit breakers IC insertion machines Defibrillators Textile machinery Automatic tellers Film processors Machine tools Pinch rollers Brakes Ticket machines Copiers
7. Common Linear Solenoid Vending machines Brakes Copiers Door locks Pumps Interposers Coin changers Film processors Disk drive locks Electronic typewriters
8. Symbol of Solenoid Symbol of Solenoid
9. MAGNETIC FIELD LINES
10.  Solenoids converts electrical energy to mechanical work. Different types of solenoids for different types of applications.