×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

How can I find out which type of magnet Is?

How can I find out which type of magnet Is?

How can I find out which type of magnet Is?

(OP)
I repair electrical motors in a workshop and sometimes I must repair PMDC motor and other motors that their poles are made of permanent magnet.I need to specify type of permanent magnet (Ferrite or Alnico or rare earth or ...)by a simple methode.Is there any idea about it? Thanks.

RE: How can I find out which type of magnet Is?

I think I'd go out and grab my nearest ChemE or a chemistry major and talk to them. It's pretty easy to differentiate between ferrite and metallic, but between various metallic formulations is more difficult.

old field guy

RE: How can I find out which type of magnet Is?

If the magnets are part of the rotor, they almost certainly are rare earth magnets such as NdFeB or SmCo. Since there are dozens of different grades of rare earth magnets, I recommend sending a sample to a reputable magnet distributor and let them know you want them to quote a particular quantity. It would be ideal if you could send an intact magnet. It is a simple matter to non-destructively determine the material type and grade. I do this all the time, returning the sample after testing.

RE: How can I find out which type of magnet Is?

Is there a good resource for the densities of different magnets? If they differ enough, an accurate balance and a graduated cylinder to measure volume can be used. We do that with gold jewelry to determine 18k vs 14k vs the occasional 24k ring, chain, and other odd-shaped things.

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

RE: How can I find out which type of magnet Is?

Density will only tell you if it is SmCo or NdFeB, not the grade of material.

FWIW: SmCo has a density of ~8.4 g/cc. NdFeB has a density of ~7.6 g/cc

RE: How can I find out which type of magnet Is?

(OP)
Hi MagMike! Are you sure that “If the magnets are part of the rotor, they almost certainly are rare earth magnets such as NdFeB or SmCo. “? but I've seen some rotors with Ferriet magnets. evidently there is no simple, inexpensive and non-destructively way to determine the material type and grade.

RE: How can I find out which type of magnet Is?

You'll have to send it to a reputable magnet vendor and it is a fairly simple matter to determine the grade of magnet material and it is nondestructive.

RE: How can I find out which type of magnet Is?

(OP)
Thank you for your replys.

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!


Resources