How do you guys store magnetic parts (such as DC motors and speakers)

Storing DC motors and speakers has always been a challenge for me. They have magnets and I'm afraid if I put them close together or let them stick together (due to magnetic attraction) they might get weaker or get damaged. So far I've been arranging them so that they are far enough from each other that they don't get attracted. But as their number increases it's getting more and more of a hassle. I was wondering how you guys store your speakers and DC motors.

I have never worried about this (in the last 50+ years), no negative issues seen or experienced.

If you want, you can put ‘keepers’ on magnets.

larryd: I have never worried about this (in the last 50+ years), no negative issues seen or experienced.

If you want, you can put ‘keepers’ on magnets.

Some of my speakers have died before for no apparent reason and I suspect it might have been the magnets touching each other, that's why I'm worried about letting them stick to each other.

What kind of speakers ?

|500x374

larryd: What kind of speakers ?

|500x374

Second kind. I'm not sure it was because of being near other speakers I'm just guessing. Since they don't seem to have any physical damage.

Those speakers often have a keeper surrounding the back of the magnet.

It is my guess your speakers are failing from mishandling.

What is the resistance of the coils in the failed speakers ?

Your problem is you need to segregate based on the magnetic material. Only soft iron magnets will loose their magnetism because the magnetic domains are free to move and will become random instead of being aligned when first created. All other magnets use some other material which will not change without extreme external force. Paul

You store them sealed in plastic "Zip-lock" bags in order to prevent them from acquiring (magnetic) dust and the like, with a piece of cardboard over the front (and folded over the back) to protect the cone.

Moving coil speakers already have a "keeper" of sorts where the gap for the voice coil is. If the magnets degrade over time, that would indicate sub-standard and patently unusable quality. I have not come across that. The usual failure modality of speakers is physical damage, moisture and corrosion of the voice coil which becomes open circuit. The magnet is generally perfectly fine.

The same applies to motors - the magnetic circuit is totally enclosed within the housing and cannot be influenced by external fields, but you do need to protect them from debris to some extent.

For speakers tape a piece of cardboard to the front and something the back to prevent stuff damaging the cone. Everything else gets chucked in a draw with no regard for it’s safety. Speakers and motors already have their poles close together, you won’t demagnetise them without some serious effort. You really don’t need to worry unless you’re trying to store tiny low strength magnets with super powerful monsters.

Both speakers and motors have metal parts to "contain / guide" the field to a gap internal to the device. For instance in a speaker the gap is there the voice coil goes.

So anything you do will be driven by: 1) not ripping the speaker cone 2) not getting magnetic debris in a motor.

Thank you everyone. I guess I don't have to worry about this anymore. I didn't know about magnetic dust. Will make sure to keep them in zip bags from now on.

This is gonna make my life a lot easier :)

larryd: What is the resistance of the coils in the failed speakers ?

I'll check and report back.

Drag a magnet through the dry dirt around your home and see what you pick up! Paul

pourduino: Storing DC motors and speakers has always been a challenge for me. They have magnets and I'm afraid if I put them close together or let them stick together (due to magnetic attraction) they might get weaker or get damaged. So far I've been arranging them so that they are far enough from each other that they don't get attracted. But as their number increases it's getting more and more of a hassle. I was wondering how you guys store your speakers and DC motors.

In the packing they came in if possible. Other wise just be careful handling and try to keep from bashing into each other. Bubble-wrap would be one way to protect them.

Paul_KD7HB: Your problem is you need to segregate based on the magnetic material. Only soft iron magnets will loose their magnetism because the magnetic domains are free to move and will become random instead of being aligned when first created. All other magnets use some other material which will not change without extreme external force. Paul

Soft iron magnets maintain their magnetism longer when stored together rather than separately.

Speakers as in the second photo are often shipped and stored with the coil shorted out to minimize core movement.

OP - I store magnets and speakers in a box with the only precautions being to protect the cone from physical damage. I have some speakers that are more than 50 years old that still work just fine.

SteveMann: Soft iron magnets maintain their magnetism longer when stored together rather than separately.

So true. This is why very old meter movements loose their accuracy. Years ago I built a 1920's style regenerative radio that used a battery for filament power. I bought a 0-5 volt meter of a similar age. It would barely read any voltage because of the magnet age. Paul

larryd: What is the resistance of the coils in the failed speakers ?

As it turns out I currently have only one damaged speaker. Either I have thrown out the broken ones, or my tests in the past have been incorrect. The resistance of the broken one is 8ohms (as read by DMM). But it doesn't look so good physically. Looks a bit rusty and the cone thingy looks a bit deformed. Given what you and others in the thread have said I guess this one is just suffering from physical damage. Thanks again for your help.

SteveMann: Soft iron magnets maintain their magnetism longer when stored together rather than separately.

Yes but magnets can be stacked together with their S/N poles perfectly aligned. But speakers and motors have irregular shapes and they may attach to each other even tho their poles aren't perfectly aligned. And that's what I was worried about.

I store magnets and speakers in a box with the only precautions being to protect the cone from physical damage. I have some speakers that are more than 50 years old that still work just fine.

Oh that's nice. That's what I was hoping to hear, someone who has actually stored them for years with no problem. Thanks.

Well the point is they either use good quality magnets - as most in the last 30, 40 or 50 years would - or they don't. :astonished: