A typical solenoid consists of the following main elements:
- a cylindrical coil
- a steel or iron frame or shell
- a steel or iron plunger
- a stationary magnetic pole/travel stop (optional)
A magnetic field is generated within the solenoid by passing an electrical current through the coil. The frame or shell surrounds the coil, providing a path for flux. In effect, it focuses the magnetic field produced by the coil.
The plunger, being made of a highly magnetic material, reacts to the magnetic field by attempting to move to the centre of the coil. The plunger will travel to the centred position unless stopped by a load which exceeds the solenoid’s force capability, or the plunger contacts the stationary pole/travel stop.
The force generated by a solenoid is dependent upon the current flowing through the coil windings.
