Solenoids are electromechanical devices which convert an electromotive force into mechanical motion and a useable force. The simplest form of a solenoid might be the solenoid used in the door chimes at your home.
The most common solenoids are generally referred to as linear solenoids which can be designed as push or pull types. Rotary solenoids are also available, but are more complex in design.
When the coil is energized, by passing current through it, the electromotive force established pulls the solenoid plunger into the coil. Push type solenoids work exactly like pull types; however the useable force is transmitted by a push rod or equivalent which extends through and is free to move through the solenoid stop.
Solenoids are used in a myriad of different industries. One such example is Material Handling. Two critical components of ensuring plant operations run smoothly and without interruption are identifying material levels (such as in feeder bowl applications), and part or machine indexing (such as in conveyor belt positioning). Loss of signal or movement can shut down an otherwise smoothly running operation. Solenoids provide reliable indication and movement on critical plant equipment, the failure of which would be extremely costly in terms of time and other resources.