I have read and heard that magnets last 500 years. This would be great if it would be under a load.
But my question is why so many magnet motors fail even after they seem to work. I am 48 years old and have seen many magnet test and even motors at school as I was growing up. Some motors that where hooked up to a gernerator and only last about a month or so before they end up disasembling them. In my mind it tells me that a magnet under a load depolarize after a bit. This is why I havn't done much with magnets.
Can anybody tell me where to find life expectentcies under a load for a magnet?
Some things I have read...
Modern "super" magnets are different from older permanent magnet technologies. I think there is a "knee" above which a magnet can be de-magnetized, when in repulsion, but as long as you work below this knee, you are safe.
Just what I have gathered from the web.
Quote from: AB Hammer on October 16, 2007, 01:24:28 PM
But my question is why so many magnet motors fail even after they seem to work. I am 48 years old and have seen many magnet test and even motors at school as I was growing up. Some motors...
Please show me a single working magnet motor.
Please, please! I?m dead serious and not joking at all.
I?ve never seen one in my whole life and my training as well as my related experience (what a waste of time!) deny them.
Show me at least one clearly working for 5+ minutes and I?ll be more than grateful. What the heck, I?ll be even ready to re-write some of the science!
Again, I am very serious in my kind request and I suppose a lot of other members here would like to see it too.
Many thanks in advance,
Tinu
@ Tinu,
I believe he is speaking about conventional magnet motors ( coils and wires and such) that run a generator.
Jason
G'day Hammer and all,
I have handled many motors in my life that used permanent magnets, some of them have been running since the 1940's and 1950's without apparent diminishing of the magnetic field.
The one thing though that will knock the magnetism out of ANY magnet is heat. Some magnetic materials are more heat tolerant than others but all suffer from that flaw. The motors you describe sound to me like motors that ran too hot for what they were designed to do, usually due to overload or poor ventilation.
Hans von Lieven
Nastrand2000
No I am talking about stationary magnet motors that connect to a generator. This is not a new story, it has just found new life.
Now for this one found on youtube.
http://www.youtube.com/watch?v=PFGiWiXMHn0
I find it very impressive. But the ones I knew of years ago where also very impressive at first, but they are not here no more. Simply what happened?
hansvonlieven
You posted as I was posting, so I am editing. "Heat" that could very well explain why the ones I have known about are no longer around. Thanks that may be the real answer I have been looking for.
I am not saying that this is necessarily the case, as there are other phenomena that will knock out magnetism, a sharp blow with a hammer for instance can destroy some of the old alnico magnets.
But, by the same token, in motors, the only verifiable cause for demagnetising the magnets that I found has been excessive heat.
Hans von Lieven
@AB Hammer
May I direct you to an older thread here where eddy currents may have caused demagnetization in a working permanent magnet motor, see here: http://www.overunity.com/index.php/topic,828.msg8155.html#msg8155
So using ceramic/ferrite magnets is a possibility to avoid eddy currents, hence heat.
Gyula
Quote from: AB Hammer on October 16, 2007, 04:14:22 PM
No I am talking about stationary magnet motors that connect to a generator. This is not a new story, it has just found new life.
Now for this one found on youtube.
http://www.youtube.com/watch?v=PFGiWiXMHn0
The Perendev magnet motor you refer to in this link is a well known fake.
This is not a good example of a working magnet motor.
@Honk
Are you sure it is fake? So how did they do this video?
Isn't anything sacred anymore?
OH SMEG!!! I got fooled, but I don't follow the magnet motor seen that much eather. But it looked similar to the old ones I new of.
Quote from: wattsup on October 17, 2007, 11:18:13 AM
Are you sure it is fake? So how did they do this video?
Isn't anything sacred anymore?
The Perendev have been around for ever now but they have never shown any demonstration model
or let anyone examine their claimed self running magnet motor. Nor have they ever delivered any motors.
Just ask Stefan (moderator). He know it's a fake. Perhaps he's got some inside information!!!
Quote from: AB Hammer on October 16, 2007, 01:24:28 PM
I have read and heard that magnets last 500 years. This would be great if it would be under a load.
But my question is why so many magnet motors fail even after they seem to work. I am 48 years old and have seen many magnet test and even motors at school as I was growing up. Some motors that where hooked up to a gernerator and only last about a month or so before they end up disasembling them. In my mind it tells me that a magnet under a load depolarize after a bit. This is why I havn't done much with magnets.
Can anybody tell me where to find life expectentcies under a load for a magnet?
AB yes its so ,
somes magnets from soft iron ,
have this effects.
Bicycle (light)generators (dynamo)
Dynamo-hand-flash-lamps
,ost people kow that that it go darker and darker.
Even before WW2 . Laudspeacker Magnet must als
new magnetized after years , because that go week !
(not only the tubes!)
G.Pese
NOW , "i hope this is right" that the new ferrit-ceramic types are "solid-state"
Only "stessing" (overload) will not accepted.
heat ? not such problem , at heat , magnetpower will comes week , if
heat go down , power recover again.
(Magnet controlled "solder-irion" from Weller-Germany use this
in his devices . (Magnetfield switch an relais) figued out at an solder temoerarure
about 300 ? C .
(BUT i controled this - abter Years , it LOST from the controlled Temperature ,
say the magnetpower go steady over years down.
G.Pese