Re: How does a Solenoid work?
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.
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.
The second kind when activated moves an arm or something. An example would be a fuel shut off solenoid or valve. You hit the switch it activates the solenoid and a valve opens or closes.
A Shift-solenoid starter like on new cars does both. You hit the switch and starter drive gear is pushed out and power is transfer to spin the starter at the same time. The solenoid is part of the starter. A bendrix starter has a solenoid away from the starter and force of the spinning starter moves the gear out.
Most solenoids have two large post/terminals and one or two small ones. A single small one is the activation power. A second small one would be a ground. Some ground thru the mounting bolts and would have no second post. The two larger ones transfer power from one side to the other. A solenoid that moves an arm would not have any large posts and may have one or two small posts.
It is easier for me to show someone how it works, but I hope this helps.
Mike