Understanding the physics behind a Solenoid Valve

In summary: This is because the steel becomes magnetized by the current in the solenoid, and the force between the two magnets is strong. In summary, the functioning of a solenoid depends on the interaction between the magnetic force created by the current and the spring force. When the solenoid is energized, the plunger is pulled in against the spring force, but when the current is cut, the spring force pushes the plunger back down. If the plunger is a permanent magnet, the current must be adjusted to ensure an attractive force between the solenoid-magnet and plunger-magnet.
  • #1
jackmrrabbit
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TL;DR Summary
In the scenario where a permanent magnetic is placed inside a solenoid (like a solenoid valve) I am confused regarding the physics of how the EMF generated by running current through the solenoid keeps the permanent magnetic elevated (open in a normally closed solenoid valve) over time.

Doesn’t induction only occur due to a changing magnetic field? If the permanent magnetic reaches its max displacement, why is there still a force keeping it elevated? Any help would be much appreciated.
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  • #2
I don't believe this has anything to do with induction. It has to do with whether the solenoid is energized or not. The current in the solenoid turns it into a magnet and the plunger, made from some kind of magnetic material, will be pulled in against the downward spring force to minimize the magnetic potential energy. Of course, for this to work, the spring force must be weaker than the magnetic force. When the current to the solenoid is cut, the magnetic force disappears and the spring pushes the plunger back down.

On edit:
If the plunger is a permanent magnet, the current in the solenoid must be such that the force between the solenoid-magnet and plunger-magnet is attractive.
 
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Likes Lnewqban and jackmrrabbit
  • #3
kuruman said:
I don't believe this has anything to do with induction. It has to do with whether the solenoid is energized or not. The current in the solenoid turns it into a magnet and the plunger, made from some kind of magnetic material, will be pulled in against the downward spring force to minimize the magnetic potential energy. Of course, for this to work, the spring force must be weaker than the magnetic force. When the current to the solenoid is cut, the magnetic force disappears and the spring pushes the plunger back down.

On edit:
If the plunger is a permanent magnet, the current in the solenoid must be such that the force between the solenoid-magnet and plunger-magnet is attractive.
That makes a lot more sense. Thank you!
 
  • #4
If you place a piece of steel next to the top of the solenoid while energized, you will feel a strong magnetic force.
 

What is a solenoid valve?

A solenoid valve is an electromechanical device that uses an electromagnetic coil to control the flow of a fluid or gas through a pipe. It is commonly used in various industries, such as manufacturing, automotive, and medical, to control the flow of liquids or gases in a system.

How does a solenoid valve work?

A solenoid valve works by using an electromagnetic coil to create a magnetic field. When an electric current is passed through the coil, the magnetic field attracts a plunger or armature, which opens or closes the valve. This allows the fluid or gas to flow through the valve or stops it from flowing.

What are the main components of a solenoid valve?

The main components of a solenoid valve include the coil, plunger or armature, valve body, and a spring. The coil is responsible for creating the magnetic field, while the plunger or armature is attracted to the magnetic field and controls the opening and closing of the valve. The valve body is the main housing of the valve, and the spring helps to return the plunger or armature to its original position when the electric current is turned off.

What factors affect the performance of a solenoid valve?

The performance of a solenoid valve can be affected by various factors, including the type and quality of the material used for the valve body, the strength of the magnetic field generated by the coil, and the design of the plunger or armature. Other factors such as temperature, pressure, and the type of fluid or gas being controlled can also impact the performance of a solenoid valve.

What are the advantages of using a solenoid valve?

There are several advantages to using a solenoid valve, including its fast response time, precise control of fluid or gas flow, and its ability to be easily automated and integrated into a larger system. Additionally, solenoid valves are durable, reliable, and require minimal maintenance, making them a cost-effective choice for many applications.

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