×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Saturation of a Magnetic Frame

Saturation of a Magnetic Frame

Saturation of a Magnetic Frame

(OP)
Is it feasible to determine whether or not a magnetic frame is saturated by the following experiment?

Device: A small solenoid, approx 1.5inch by 2.0inch.

Method:  
The solenoid is secured in a non-magnetic fixture.
The armature position is fixed half way along its stoke.  [full stroke approx ¼ inch]
The armature is attached to a force gauge via a non-magnetic rod.
The coil power is increased at regular intervals whilst readings are recoded off the force gauge.

Prediction:  The reading with the greatest magnitude is the point where the amp-turns are sufficient to saturate the magnetic circuit.

I appreciate that the efficiency of the magnetic circuit will be reduced by the air gap (approx 1/8 inch), but will this simple experiment provide me with sufficient information to determine if the coil frame is fully saturated?  Thermal considerations negated.

I’d appreciate your comments:

Thanks & regards,

RE: Saturation of a Magnetic Frame

Probably not possible.

If the amp-turns aren't sufficient to saturate the frame, then a max force reading is meaningless.  

In addition, the solenoid may not have been desigend to operate near saturation. They are most efficient when operating in a region of high permeability which occurs before saturation.

RE: Saturation of a Magnetic Frame

(OP)
Thanks Mike.

I can confirm that I will be able to generate enough A-ts to saturate the frame.  Also, to be clear, I should have mentioned that this is a DC solenoid.

I was hoping the exp will also show me how much power is required to fully saturate the frame, and to define the point on the curve where normal operation occurs.  What i'm not sure about is (a) if this exp is feasible and (b) the best position for the armature e.g. fully open (max air gap), mid way, or just off its stop (min air gap).

RE: Saturation of a Magnetic Frame

Sure you can do this.
If you have enough field then I would expect to see the curve come out looking just like a magnetization curve.
As you crank the field you will continue to get increased force, but it will increase very slowly once you are into a region of lower permiability, even if you haven't reached saturation.
You can easily test at different locations, this somewhat depends on design and leakage factors, but hte highest force should be with the smallest air gap.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm

RE: Saturation of a Magnetic Frame

(OP)
Thanks Ed.

That's what I was thinking.

So, for this method, I have one vote for and one vote against.

Kind regards,

RE: Saturation of a Magnetic Frame

Why not just calculate the magnetic circuit and see if it is saturated or, even better see at each distance how many amper turns needed to saturate the electromagnet. Who told you that the frame will be the saturated part? It may be the plunger. Thats depend on the design of the electromagnet. Only calculations will tell you which part will saturate first and where.

RE: Saturation of a Magnetic Frame

Saturation is a gradual effect with most magnetic materials.  You will not see a peak or even a sharp knee in your force vs amp-turns curve, just a change in slope.  Plot the first derivative to find saturation.

Be sure to measure actual current and not supply voltage because the resistance of your winding will go up as you increase power to the solenoid.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close