Understanding the physics behind a Solenoid Valve

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    Physics Solenoid Valve
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SUMMARY

The discussion centers on the operational principles of solenoid valves, emphasizing that the functionality is dependent on whether the solenoid is energized. When current flows through the solenoid, it generates a magnetic field that attracts a plunger made of magnetic material, overcoming the downward force of a spring. The magnetic force must exceed the spring force for the mechanism to function correctly. Once the current is cut, the magnetic force ceases, allowing the spring to return the plunger to its original position.

PREREQUISITES
  • Understanding of solenoid mechanics
  • Basic knowledge of magnetic forces
  • Familiarity with spring dynamics
  • Knowledge of electrical circuits and current flow
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  • Research the principles of electromagnetic induction
  • Study the design and applications of solenoid valves in automation
  • Explore the characteristics of different magnetic materials used in plungers
  • Learn about the effects of varying current levels on solenoid performance
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Engineers, technicians, and students interested in fluid control systems, automation technology, and electromagnetic applications will benefit from this discussion.

jackmrrabbit
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TL;DR
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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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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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!
 
If you place a piece of steel next to the top of the solenoid while energized, you will feel a strong magnetic force.
 

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