no cogging in CD motor

[Keith43221]

After busting all my magents out in a crash, i tried to put them back in. But When i put my bell back on my motor, there is no cogging. it turns freely. there is a part where is does a little, but i think that is just some magents hitting the stationer. I'm not sure what i did wrong. maybe i didn't get NSNS.
How am i suppose to do that anyways? I've about in a few places, but never understood how its done.
Thanks, Keith.
(btw: I just ordered new magents for this motor) (and i didn't build this motor)

[pda4you]

Clogging is a dance. Cogging is what you are after!

It is odd that a crash would de-mag the magnets - strange.

Mike

[Keith43221]

lol, thanks mike.
ps. I didn't build this motor, thats why im clueless.

[ecologito]

one way to know if they are NSNSNS.. orientation, take 1 magnet and, as you go around the bell one magnet should atract it and the next one should pull it away. if you have 2 magnets next to each other doing the exact same thing to your magnet you have them oriented wrong. A good tutorial about magents is here:

http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=de_en&trurl=http%3a%2f%2fpowerditto.de%2fMagneteinbau.ht ml

[Keith43221]

Thanks, ecologito, i'll go try that right now.

[Keith43221]

well,you were right ecologito.
So, to remove the magnets, i followed some advice my somone on here. Just burn them out over a small (hot) fire. Well, did that, and now i just have some little peices of metel. But lucky, i am getting some magents for christmas, (with a spacer) so, soon, i will be all fixed. Thanks guys.

[lensrc]

The burning thing is usually used to remove the useless ring magnet in a scavenged CD Rom motor. I hope you had some good ventilation when you did the burnout, as neodymium is toxic, as I imagine the ring mags are when burned out.

Len

[Keith43221]

yea, i did it out side. Well, what is the recommed method for just removing magents from the can?
Thanks, Keith

[lensrc]

I just use a hobby knife to get behund them and pop them out. Then scrape out the old glue. I dont really do this often, as it is much faster for me to just assemble a new rotor with the old shaft. I trade off the old parts to my buddies and let them scavenge. :D

Len

[oldphart]

just a couple of hints.
1. to remove magnets ,soak the rotor assy overnight in cellulose thinners,it seems to soften,not completely disolve any adehisive .Only use heat on the original moulded magnet
2 to ascertain polarity,allow the loose magnets to form a "stick" of magnets,they will automatically form up in NSNS formation ,then put a dab of coloured nail varnish,or something similar on the face of the first one.Then,with a sharp hobby knife slice them off the stack one at a time,putting a dab of varnish on each one as you go.(Beware .the magnets can fly all over the place,a large magnet is usefull to find errant ones.)
It may prolong the process,but it helps to allow each dab of varnish to dry before going onto the next magnet.

[ecologito]

Another easy way to remove magnets is throwing the can in the freezer for a couple of hours.

[osmium_192]

How does freezing it help?

Anyways, Neos are EXTREMELY heat sensitive. The standard magnet has a temperature rating of about 60 to 70 deg C where it will lose its magnetism but will restore most of it back when cooled. If heated to 80 deg C it will permaneantly lose some magnetism and if heated past its curie temperature of a few hundred degrees (easily achieved by flames) it will Permanenantly be demagnetised.

Owen

[BrunswickOH]

Clogging is a dance. Cogging is what you are after!

Why?? Some motors cog more then others, I've never noticed any performance related to how much a motor cogs or doesn't. Some of my best motors hardly cog at all. So I'm curious why you feel that a motor needs to cog a lot.



Jim

[galloping gimp]

Same here, Jim. I have not seen any correlation between cogging and motor performance, whether in commercial motors or my own creations.

- Jeff

[ryanl2006]

I think he was just saying that cogging is the correct term, not clogging.

Also, if an outrunner has a very small airgap and the magnets are very strong, it cogs pretty hard. In that sense it can be a good sign, but the rest of the motor still has to be well made to make it perform over all. This does not apply to innrunners as they are a whole different ball game.