×
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

Hello all, I am new to the forum an

Hello all, I am new to the forum an

Hello all, I am new to the forum an

(OP)
Hello all, I am new to the forum and I regret to tell that, although I am an engineering enthusiast and do play around with concepts for my engineering team to understand my needs from the market, actually I am a Marketing Director. I hope this is not a reason to reject my participation here.

I am working on a project that requires some sort of non-mechanical latching system, and the customer is asking to use magnets.

The idea would be to use a permanent magnet to attach to a moving part that needs to be retained at a certain position. The fix part would be an electromagnet with an iron core: the idea is to release the moving part that has attached to the core of the electromagnet by applying a current to the electromagnet with an inverse polarity to that one of the fixed magnet, provoking a repulsion force.

In this way, when the moving part carrying the permanent magnet enters in contact with the fixed unenergized electromagnet, the system would be attracted and thus remain in that position. As soon as the electromagnet receives a current, the repulsion force would make the system detach.

Is this just a stupid nonsense out of a ridiculous marketing mind? ponder

Is there any literature I can find to understand how to dimension both elements?

Forum manager: if this topic is not in the right position please feel free to move it where it belongs.

Thank you all for your attention.

Regards from Barceona.

Joan.

RE: Hello all, I am new to the forum an

I realize the concept seems simple and straightforward, but the practical details to make this work are extremely challenging.

Unless minimal retaining forces are involved, it will require a lot of power to the electromagnet to produce a sufficiently strong repulsion force.

To evaluate feasibility, can you answer the following:
Approximately how much retention force is required?
How large is this going to be?
How much power is available to energize the electromagnet?

I am not aware of any literature that would directly address a design like this.

RE: Hello all, I am new to the forum an

(OP)
Thanks for your reply!

So it is clear that a dumb question is always more difficult to reply than a question from an expert, huh!

To put this into a more graphic terrain, just imagine a drawer into a cabinet that needs to be hold in the closed position with a pushing spring that would try to open it. The electromagnet is unpowered and the permanent magnet is keeping the drawer in closed position.

As soon as I want to open the drawer I switch the electromagnet on and the magic happens.

Those would be more or less the conditions. The dimension is in the order of centimeters or millimeters.

RE: Hello all, I am new to the forum an

(OP)
Hi IRstuff, thanks for your comment.

I have looked into those, and it seems that they use the current to keep the dore closed. As soon as the power is off the spring opens the door.

The problem is that this system is using power continuously and I want to make an energy efficient system. So I need to do it the other way around.

RE: Hello all, I am new to the forum an

Still unclear about the level of retention force. Cabinet doors sometimes have magnetic latches, but they're relatively easily opened by pulling a bit harder. For stronger retention forces, ala tens of pounds of force, you run into the problems alluded to by MagMike.

The alternative is to use mechanical advantage to move the magnet away from the metal surface it touches. see Switchable Magnetic Base here: https://www.thorlabs.com/newgrouppage9.cfm?objectg...

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Hello all, I am new to the forum an

These were used commonly in signs to latch elements. There is a fine balance between the the holding force, current to unlatch, and the risk of demagnetizing the magnets.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

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