What does a solenoid do?

[fussle]

This might be a dumb question, but I am not all too familiar with battery or starter solenoids. I know that it is a coil of wire carrying electrical current, but I am not sure exactly what its purpose is. If anyone could shed light on this matter, that would be great.

 

[Ralgha]

A solenoid is basically a switch that uses the magnetic field generated by a coil of wire to actuate the mechanical portion of the switch.

 

[JRSLim]

Solenoids

A solenoid is basically a way to open a higher capcity switch via a smaller switch. For example to initialize the starter, when you turn the ignition switch to tthe start position, it contacts and allows some current to flow and energize a solenoid that closes the circuit to the starter. In the solenoid is a coil and a solid core, when energised, the core moves and closes the circuit for current to flow. A Relay is similar to to a solenoid, only the core is stationary in a relay.

 

[TonyC]

This might be a dumb question, but I am not all too familiar with battery or starter solenoids. I know that it is a coil of wire carrying electrical current, but I am not sure exactly what its purpose is. If anyone could shed light on this matter, that would be great.

A solenoid, in general, is that coil of wire to which you referred that most commonly is found in the shape of a cylinder. When it carries a current, it acts like a bar magnet and can thereby perform work, that is it can move something. The coil of wire, then, simply converts electrical energy into mechanical energy. The electromagnet, if you will, moves something.


In the case of your starter solenoid, the something it moves is an iron core. That iron core is normally springloaded to one end of the switch; the application of electrical current to the solenoid coil creates a magnetic field that moves the iron core to the opposite end of the switch. It is at this point that the sliding core bridges the gap between two electrical contacts, allowing current to flow from one to the other. In the case of your starter solenoid, the circuit completed is that of the battery to the starter. It has the same effect as connecting a wire directly to your starter terminal and then touching it to the (+) post on your battery. Advantages, however, of the starter solenoid arrangement is there is no open spark, and you don't have to get out of the driver's seat to do it. A low amperage flow from your ingition switch to the solenoid energizes the electrical field of the starter solenoid, the rod moves, and you have a high-amperage flow of electricity to the starter motor.

Your dishwasher also uses a solenoid. An electrical current is applied to a spring-loaded water valve to open the valve and allow the flow of hot water to the dishwasher. Your washing machine uses 2 - - one for hot water, and one for cold. Your refrigerator with icemaker and cold water through the door uses two - - one for the icemaker, and one for the water dispenser. Go ahead, grab a cup and try it. Every time you push the button, you activate the solenoid.


Now that you know so much about solenoids, you can retrieve the working solenoid from the next appliance you're about to throw away and figure a way to work it into Junior's next science fair project.

 

[qmaster3]

This might be a dumb question, but I am not all too familiar with battery or starter solenoids. I know that it is a coil of wire carrying electrical current, but I am not sure exactly what its purpose is. If anyone could shed light on this matter, that would be great.

Having Car problems? A lot of shops will tell you it's your starter solenoid that's bad. 50% of the time it's the starter/engine block mount area that needs to be cleaned. It doesn’t take much to pull a starter off, run it down to AUTO ZONE and have it bench tested. If a shop did tell you this make sure you ask for the old starter, and still take it to get the "bench test" at Auto Zone. If it's good have your wife go in there in B*tch. It always works.



If you're not having car problems then you got free info. I usually charge for this stuff

 

[avbug]

As other posters have explained, a solenoid is an electrical switch that does something. The function of the solenoid is to cause linear movement; to move the core of the solenoid out of the solenoid assembly. The solenoid may be used to block or open hydraulic flow, to actuate an electrical mechanism, or to create a mechanical movement to actuate, stop, limit, or move an item. Actuators are used in pneumatic systems to control pressure, to move valves , control to jet pumps. Solenoids are used in virtually every type of system in most advanced aircraft.

A steering actuator, for example, may be controlled by a solenoid, or solenoid(s) which open and close hydraulic ports to control hydraulic pressure. A measuring device called a potentiometer will determine what deflection you want when you try to control the nosewheel, and another will measure where the nosewheel is, and then a logic circuit will actuate solenoids to control the hydraulic fluid that moves the nosewheel actuator.

So far as the car is concerned...before you go pulling the starter to have it benched at autozone, if you're concerned about a bad ground, use one side or the other of a set of jumper cables to test by providing a good ground. You'll know right away. While you're there, if you can jump across the starter contacts with a heavy screwdriver (wear a glove or insulate it, and wear safety goggles (while the car is not in gear...) and get starter action, then you've got a switch or solenoid problem. The starter is fine.

Most of the time today, the solenoid is integral to the starter motor; if you have a problem with either one, you need to replace the assembly.

 

[qmaster3]

fussle,

Don't go hooking jumper cables up to your starter. You are asking for trouble. And a bunch of OBDII codes (check engine lights) flashing. The reason you need the bench test is because of proper load factors. I brought this up, because I don't want you to get ripped off. If you are going to rip into it PM me.

 

[TonyC]

... (wear a glove or insulate it, and wear safety goggles ...

Wuss.

 

[avbug]

Wuss.

Absolutely. I don't do amperage well.

Don't go hooking jumper cables up to your starter.

I didn't tell him to run voltage on those cables. The point of using the jumper cables is to provide a ground...not to try running power directly to the starter. That's already happening with way the starter is configured. And by using a screwdriver over the contacts on the starter, you're doing exactly the same thing.

Additionally, you're not going to hurt the starter by benching it yourself and using a battery with cables across the solenoid.

In the car, you can use either the red side or the black side of your cables to form a path to ground to determine if that's all youre facing on the vehicle...this is a proper maintenance practice, and you won't set off any codes or damage anything on the car. You're merely bonding the starter to the engine block.

 

[qmaster3]

The OBDII codes come from when you try to do things like this, and it goes wrong. I know the language you're talking, but does fussle? Better explain it better to him.