How does a Solenoid work?

[Miami Criminal Law]

I have googled this issue trying to learn for myself before I made this post. I know a solenoid is a solid core with wires wrapped around it that creates a magnetic field that starts something in motion. But in an outboard motor...what is it that goes into motion when the magnetic field is created by the solenoid? THis may be a stupid question and if no one answers it i wont be offended.

 

[Barnacle_Bill]

Re: How does a Solenoid work?

There is a plunger inside the solenoid that makes contact across 2 high amperage contacts inside it when it is actuated. It takes very low amperage to actuate it while provide high amperage to something like a starter.

 

[Silvertip]

Re: How does a Solenoid work?

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.

 

[Mike722]

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