Solenoids?

[apacheguy]

All too often on these forums I see people throwing around the vague, non-descriptive word "solenoid". Can someone please define what they mean by solenoids?

A solenoid (per Wikipedia) is a metal coil. However, I know that it can also refer to valves/gauges/God knows what else. I would be very appreciative if folks would use a more descriptive term next time they post. Instead of saying, "Oh, well it's probably a bad solenoid" please be more specific as that gives me very little information.

 

[AndreN]

A solenoid is basically a wire coil around a hollow center. When electrically energized, the coil becomes an electromagnet, pulling in a metal rod. The rod's connected to something that needs to move linearly. For example, pinball machines use solenoids to move the flippers (the metal rod pulls on a lever that turns the shaft the flipper is mounted on). In cars, solenoids are most often used to engage the starter gear or to lock/unlock the doors. The Model S doesn't need/use solenoids for either of those things.

Solenoids can go bad. Usually either the wire in the coil breaks somewhere (solenoid stops working) or the insulation melts somewhere on the wire, leading to a short and probably a blown fuse. Solenoids usually have a return spring to move the metal rod back out of the solenoid when the power is cut off, and those springs can wear out and break as well.