A solenoid valve coil, which typically has a copper or aluminum wire, is often used to generate linear motion out of electricity. The coil is made up of a wire wrapping around a hollow space containing a ferromagnetic core. Configured such that a magnetic field is created by the structure, the unit generally uses this magnetism to move a valve plunger. This component is often the ferromagnetic core in a valve, which can trigger it to open and close. Most of the time, a solenoid valve coil can operate on many different voltages, and is often available in a variety of constructions.
Able to operate on direct current (DC) or alternating current (AC), solenoid valve coil models can come in a variety of voltages. Some operate down to six volts, while others are compatible with 220 or 240 volt systems. Novices to electrical science typically benefit from low-voltage types because the chances of getting a shock are less. Many 12 volt AC types of solenoids are suited for hobbyists, while the DC versions are often used with industrial machinery. Usually a DC coil is be used with positively or negatively charged wires on either terminal.
The magnetic field in a solenoid valve coil is typically reversed by changing the polarity of the electrical current. In some cases, that magnetic field will reverse while the valve plunger may be pulled in the same direction, if its induced polarity reverses as well. This effect most often occurs when iron plungers are built into the solenoid valve coil, rather than bar magnets.
Various solenoid valve coil configurations are available from manufacturers. A tape wrapped coil typically features a spool-like component with the conductor wire looped around it. Insulation tape is wrapped around the wire. Encapsulated coils are different in that a resin is used to cover the wire, and are generally more protected against moisture. The wires tend to be stronger as well, so encapsulated varieties are often used in industrial environments.
Some kinds of solenoid valve coil come with a connector instead of lead wires. Metal prongs or pins extend from the coil casing and a plug in a female configuration connects to it. Components can be quickly replaced this way, instead of repairing a solenoid valve coil, and such models are often better insulated and protected from water getting inside. These kinds of coils often come in a few standard sizes, while different ones can be used with one valve, depending on the brand.