[Bth8]

In an automobile ignition system, the starter solenoid acts as a relay, bringing metal contacts into place to close a circuit. The starter solenoid receives a small electric current when the car's ignition is activated, usually by the turn of the key. The magnetic field of the solenoid then pulls on the contacts, closing the circuit between the car's battery and the starter motor. The starter solenoid requires a constant flow of electricity in order to maintain the circuit, but because the engine is self-powering once started, the solenoid is inactive for most of the time.

[Xaxo]

Like all magnets, the magnetic field of an activated solenoid has positive and negative poles that will attract or repel material sensitive to magnets. In a solenoid, the electromagnetic field causes the piston to either move backward or forward, which is how motion is created by a solenoid coil. here

[Mahkul]

A solenoid is a coil of wire in a corkscrew shape wrapped around a piston, often made of iron. As in all electromagnets, a magnetic field is created when an electric current passes through the wire. Electromagnets have an advantage over permanent magnets in that they can be switched on and off by the application or removal of the electric current, which is what makes them useful as switches and valves and allows them to be entirely automated. here

[draglin33]

Solenoid is the generic term for a coil of wire used as an electromagnet. It also refers to any device that converts electrical energy to mechanical energy using a solenoid. The device creates a magnetic field from electric current and uses the magnetic field to create linear motion. Common applications of solenoids are to power a switch, like the starter in an automobile, or a valve, such as in a sprinkler system. more

[tuxsoul]

In a direct-acting valve, electric current activates the solenoid, which in turn pulls a piston or plunger that would otherwise block air or fluid from flowing. In some solenoid valves, the electromagnetic field does not act directly to open the conduit. In pilot-operated valves, a solenoid moves the plunger, which creates a small opening, and pressure through the opening is what operates the valve seal. In both types, solenoid valves require a constant flow of electrical current to remain open because once the current is stopped, the electromagnetic field disperses and the valve returns to its original closed position. more

[migrainerelief4]

Solenoids are incredibly versatile and extremely useful. They're found in everything from automated factory equipment to paintball guns and even doorbells. In a chime doorbell, the audible chime is produced when a metal piston strikes a tone bar. The force that moves the piston is the magnetic field of a solenoid that receives electric current when the doorbell is pushed. more

[concetxos01]

Re: How does a Solenoid work? more

[kupan787]

Good description. The reason "why" a solenoid is required is without one, the wires to the ignition switch and back to the starter would need to be the same size as the battery cables. The ignition switch would need to have terminals on it the same size as the solenoid. Just not practical -- not to mention expensive and heavy. more

[sputnik]

I know of two kinds of solenoids, both work the same way but do two different things. Both when activated create a magnetic field that move parts inside the solenoid. The activation is power being supplied to the solenoid by a key switch, power trim, etc. more

[UnWar]

The first kind of solenoid when activated transfers power from one side to the other. An example would be a old starter solenoid or power trim. You hit the switch it activates the solenoid and power can flow to the starter or the trim motor. more

[remyroy]

A certain amount of heat is always generated when a solenoid coil is energized. The standard version of the solenoid valves has relatively low temperature rises. They are designed to reach a maximum temperature rise of 144°F under conditions of continuous operation (100%) and at 10% overvoltage. In addition, a maximum ambient temperature of 130°F is generally permissible. The maximum permissible fluid temperatures are dependent on the particular seal and body materials specified. These figures can be obtained from the technical data. [links]

[zooko]

According to the mode of actuation, a distinction is made between direct-acting valves, internally piloted valves, and externally piloted valves. A further distinguishing feature is the number of port connections or the number of flow paths ("ways").

[yeahsam51]

The particular mechanical, thermal and chemical conditions in an application factors in the selection of the seal material. the standard material for neutral fluids at temperatures up to 194°F is normally FKM. For higher temperatures EPDM and PTFE are employed. The PTFE material is universally resistant to practically all fluids of technical interest. here

[brynfrlin]

The on period is defined as the time between switching the solenoid current on and off.

[tomdetroit]

The current consumption of an AC solenoid is determined by the inductance. With increasing stroke the inductive resistance decreases and causes an increase in current consumption. This means that at the instant of de-energization, the current reaches its maximum value. The opposite situation applies to a DC solenoid where the current consumption is a function only of the resistance of the windings. A time-based comparison of the energization characteristics for AC and DC solenoids is shown in Fig. 9. At the moment of being energized, i.e. when the air gap is at its maximum, solenoid valves draw much higher currents than when the core is completely retracted, i.e., the air gap is closed. This results in a high output and increased pressure range. In DC systems, after switching on the current, flow increases relatively slowly until a constant holding current is reached. These valves are therefore, only able to control lower pressures than AC valves at the same orifice sizes. Higher pressures can only be obtained by reducing the orifice size and, thus, the flow capability. [links]

[ShonA1985]

All materials used in the construction of the valves are carefully selected according to the varying types of applications. Body material, seal material, and solenoid material are chosen to optimize functional reliability, fluid compatibility, service life and cost. more

[FreddyFender]

A: In addition to their fast-transient and relatively high current requirements and associated self-heating, they are difficult to use for precise operation of force or repeatability. However, the use of smart drivers plus position feedback via Hall-effect devices has greatly improved the situation (more on this later). here

[genjix]

A: Yes and no. Many successful solenoid design-ins use a voltage source which can supply the needed current. However, it may be hard to drive that current properly from the voltage source, since the solenoid’s relatively high transient-current demand means that the voltage source may “dip” as it tries to supply that current pulse, unless it is a stiff source with very low lead-wire resistance (such as the AC line). For this reason, many designs use a current source rather than a voltage source if they can. here

[caulinda87]

Just hearing the words “solenoid” and “relay” may conjure up visions of an ancient electromechanical word, now largely replaced by all-electronic devices, smart motors, and more. That almost makes sense, as these two components in various forms have been with us for over 150 years.

[StinkiePhish]

A: In simplest terms, it is a helically wound coil with a hollow center core along its axis. Within this core there is a free-floating plunger of magnetic material which can slide along that axis, and is located off to one end or the other of the hollow center path.

[sstsf]

Q: What are the other downsides of solenoids? here