The force applied to the armature is proportional to the change in inductance of the coil with respect to the change in position of the armature and the current flowing through the coil (see Faraday's law of induction). Although typically weak over anything but very short distances, solenoids may be controlled directly by a controller circuit, and thus have very quick reaction times. The movement of the armature is used to provide a mechanical force to some mechanism, such as controlling a solenoid valve. The coil is shaped such that the armature can be moved in and out of the space in the center of the coil, altering the coil's inductance and thereby becoming an electromagnet. Solenoid bolts, a type of electromechanical locking mechanism, also exist.Īpplications Electromechanical solenoid Ī 1920 explanation of a commercial solenoid used as an electromechanical actuatorĮlectromechanical solenoids consist of an electromagnetically inductive coil, wound around a movable steel or iron slug (termed the armature). The term 'solenoid' also often refers to a solenoid valve, an integrated device containing an electromechanical solenoid which actuates either a pneumatic or hydraulic valve, or a solenoid switch, which is a specific type of relay that internally uses an electromechanical solenoid to operate an electrical switch for example, an automobile starter solenoid or linear solenoid. In engineering, the term may also refer to a variety of transducer devices that convert energy into linear motion, more sophisticated than simple two–position actuators. Typically, it has a multiturn coil of magnet wire surrounded by a frame, which is also a magnetic flux carrier to enhance its efficiency. In simple terms, a solenoid converts electrical energy into mechanical work. Electromagnets with fixed cores are not considered solenoids. Without power, the plunger extends for part of its length outside the coil applying power pulls the plunger into the coil. In electromagnetic technology, a solenoid is an actuator assembly with a sliding ferromagnetic plunger inside the coil. The device creates a magnetic field from electric current, and uses the magnetic field to create linear motion.

In engineering, a solenoid is a device that converts electrical energy to mechanical energy, using an electromagnet formed from a coil of wire.

Electric solenoid valve engine